Performance Management
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Sep. 28, 2026 |
| LARGE CAP FUND | SIIT LARGE CAP FUND |
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| Prospectus [Line Items] |
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| Bar Chart and Performance Table [Heading] |
Performance Information
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| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
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| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
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| Bar Chart [Table] |
 | Best Quarter: 19.29% (6/30/20)
Worst Quarter: ‑23.12% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 10.83%.
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|
| Bar Chart Closing [Text Block] |
Best Quarter: 19.29% (6/30/20)
Worst Quarter: -23.12% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 10.83%.
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| Year to Date Return, Label [Optional Text] |
total return
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| Bar Chart, Year to Date Return |
10.83%
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| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
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| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
19.29%
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| Highest Quarterly Return, Date |
Jun. 30, 2020
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| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(23.12%)
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| Lowest Quarterly Return, Date |
Mar. 31, 2020
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| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
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| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
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| Performance [Table] |
Large Cap Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(6/14/1996) |
Return Before Taxes | 17.72 | % | 13.16 | % | 12.41 | % | 9.32% |
Return After Taxes on Distributions | 9.20 | % | 8.57 | % | 8.21 | % | 7.21% |
Return After Taxes on Distributions and Sale of Fund Shares | 15.20 | % | 9.43 | % | 8.79 | % | 7.31% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 10.18% |
Russell 1000 Index Return (reflects no deduction for fees, expenses or taxes) | 17.37 | % | 13.59 | % | 14.59 | % | 10.34% |
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| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
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| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
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| LARGE CAP DISCIPLINED EQUITY FUND | SIIT LARGE CAP DISCIPLINED EQUITY FUND |
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| Prospectus [Line Items] |
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| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
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| Bar Chart [Table] |
 | Best Quarter: 19.78% (6/30/20)
Worst Quarter: ‑22.77% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 10.73%.
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|
| Bar Chart Closing [Text Block] |
Best Quarter: 19.78% (6/30/20)
Worst Quarter: -22.77% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 10.73%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
10.73%
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| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
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| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
19.78%
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| Highest Quarterly Return, Date |
Jun. 30, 2020
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| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(22.77%)
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| Lowest Quarterly Return, Date |
Mar. 31, 2020
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| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
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| Performance Table Narrative |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Large Cap Disciplined Equity Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(8/28/2003) |
Return Before Taxes | 17.54 | % | 14.88 | % | 13.49 | % | 10.12% |
Return After Taxes on Distributions | 13.07 | % | 10.37 | % | 9.30 | % | 7.49% |
Return After Taxes on Distributions and Sale of Fund Shares | 12.30 | % | 10.43 | % | 9.44 | % | 7.50% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 11.07% |
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| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
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| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
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| LARGE CAP INDEX FUND | SIIT LARGE CAP INDEX FUND |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 21.71% (6/30/20)
Worst Quarter: ‑20.19% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 10.33%.
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|
| Bar Chart Closing [Text Block] |
Best Quarter: 21.71% (6/30/20)
Worst Quarter: -20.19% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 10.33%.
|
| Year to Date Return, Label [Optional Text] |
total return
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| Bar Chart, Year to Date Return |
10.33%
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| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
21.71%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(20.19%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Large Cap Index Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(4/1/2002) |
Return Before Taxes | 17.22 | % | 13.52 | % | 14.53 | % | 9.90% |
Return After Taxes on Distributions | 13.16 | % | 10.05 | % | 11.56 | % | 8.26% |
Return After Taxes on Distributions and Sale of Fund Shares | 12.63 | % | 10.04 | % | 11.20 | % | 8.00% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 9.88% |
Russell 1000 Index Return (reflects no deduction for fees, expenses or taxes) | 17.37 | % | 13.59 | % | 14.59 | % | 9.95% |
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| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
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| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
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| S&P 500 INDEX FUND | SIIT S&P 500 Index Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Bar Chart [Table] |
 | Best Quarter: 20.57% (6/30/20)
Worst Quarter: ‑19.61% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 10.16%.
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|
| Bar Chart Closing [Text Block] |
Best Quarter: 20.57% (6/30/20)
Worst Quarter: -19.61% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 10.16%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
10.16%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
20.57%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(19.61%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
S&P 500 Index Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(12/18/2013) |
Return Before Taxes | 17.81 | % | 14.35 | % | 14.75 | % | 13.63% |
Return After Taxes on Distributions | 14.69 | % | 11.21 | % | 12.69 | % | 11.83% |
Return After Taxes on Distributions and Sale of Fund Shares | 12.60 | % | 10.90 | % | 11.89 | % | 11.09% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 13.69% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
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| EXTENDED MARKET INDEX FUND | SIIT Extended Market Index Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 30.60% (6/30/20)
Worst Quarter: ‑27.81% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 17.90%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 30.60% (6/30/20)
Worst Quarter: -27.81% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 17.90%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
17.90%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
30.60%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(27.81%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Extended Market Index Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(02/28/2013) |
Return Before Taxes | 12.55 | % | 6.71 | % | 11.45 | % | 11.25% |
Return After Taxes on Distributions | 9.71 | % | 4.30 | % | 9.50 | % | 9.46% |
Return After Taxes on Distributions and Sale of Fund Shares | 9.16 | % | 4.82 | % | 8.93 | % | 8.88% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 14.51% |
Russell Small Cap Completeness Index Return (reflects no deduction for
fees, expenses or taxes) | 12.67 | % | 6.69 | % | 11.40 | % | 11.22% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| SMALL CAP FUND | SIIT SMALL CAP FUND |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 26.09% (12/31/20)
Worst Quarter: ‑31.08% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 18.10%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 26.09% (12/31/20)
Worst Quarter: -31.08% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 18.10%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
18.10%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
26.09%
|
| Highest Quarterly Return, Date |
Dec. 31, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(31.08%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Small Cap Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(6/14/1996) |
Return Before Taxes | 9.79 | % | 8.26 | % | 9.12 | % | 8.29% |
Return After Taxes on Distributions | 3.86 | % | 4.69 | % | 5.98 | % | 6.29% |
Return After Taxes on Distributions and Sale of Fund Shares | 9.47 | % | 5.70 | % | 6.47 | % | 6.34% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 10.18% |
Russell 2000 Index Return (reflects no deduction for fees, expenses or taxes) | 12.81 | % | 6.09 | % | 9.62 | % | 8.24% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| SMALL CAP II FUND | SIIT Small Cap II Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 30.14% (12/31/20)
Worst Quarter: ‑31.16% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 20.23%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 30.14% (12/31/20)
Worst Quarter: -31.16% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 20.23%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
20.23%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
30.14%
|
| Highest Quarterly Return, Date |
Dec. 31, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(31.16%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Small Cap II Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(4/10/2012) |
Return Before Taxes | 12.90 | % | 8.54 | % | 10.21 | % | 10.62% |
Return After Taxes on Distributions | 10.32 | % | 5.51 | % | 7.48 | % | 7.90% |
Return After Taxes on Distributions and Sale of Fund Shares | 9.21 | % | 5.89 | % | 7.39 | % | 7.78% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 14.58% |
Russell 2000 Index Return (reflects no deduction for fees, expenses or taxes) | 12.81 | % | 6.09 | % | 9.62 | % | 10.25% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| SMALL/MID CAP EQUITY FUND | SIIT SMALL MID CAP EQUITY FUND |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 24.37% (6/30/20)
Worst Quarter: ‑30.34% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 16.37%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 24.37% (6/30/20)
Worst Quarter: -30.34% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 16.37%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
16.37%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
24.37%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(30.34%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Small/Mid Cap Equity Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(12/15/2003) |
Return Before Taxes | 3.68 | % | 6.35 | % | 8.50 | % | 8.26% |
Return After Taxes on Distributions | 1.90 | % | 3.63 | % | 5.75 | % | 6.06% |
Return After Taxes on Distributions and Sale of Fund Shares | 3.45 | % | 4.46 | % | 6.11 | % | 6.20% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 10.89% |
Russell 2500 Index Return (reflects no deduction for fees, expenses or taxes) | 11.91 | % | 7.26 | % | 10.40 | % | 9.50% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| U.S. EQUITY FACTOR ALLOCATION FUND | SIIT U.S. Equity Factor Allocation Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing the Fund’s performance for the past seven calendar years and by showing how the Fund’s average annual returns for 1 year and 5 years, and since the Fund’s inception, compare with those of a broad measure of market performance. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing the Fund’s performance for the past seven calendar years and by showing how the Fund’s average annual returns for 1 year and 5 years, and since the Fund’s inception, compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 20.01% (6/30/20)
Worst Quarter: ‑21.75% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 11.18%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 20.01% (6/30/20)
Worst Quarter: -21.75% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 11.18%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
11.18%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
20.01%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(21.75%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
U.S. Equity Factor Allocation Fund | 1 Year | 5 Years | Since
Inception
(04/26/2018) |
Return Before Taxes | 17.99 | % | 15.18 | % | 14.16% |
Return After Taxes on Distributions | 16.26 | % | 12.23 | % | 12.06% |
Return After Taxes on Distributions and Sale of Fund Shares | 11.48 | % | 11.18 | % | 10.91% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.91% |
Russell 3000 Return (reflects no deduction for fees, expenses or taxes) | 17.15 | % | 13.15 | % | 14.18% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| U.S. MANAGED VOLATILITY FUND | SIIT U.S. Managed Volatility Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on a full calendar year. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of the Standard & Poor’s 500 Composite Stock Price Index (S&P 500 Index) (a broad-based securities market index), and three additional indexes with characteristics relevant to the Fund’s investment strategy. The Fund’s additional indexes are the MSCI USA Minimum Volatility Index (Net), the Russell 3000 Index, and the Fund’s blended benchmark that is composed of the MSCI USA Minimum Volatility Index (Net) and the Russell 3000 Value Index weighted 75%/25%.
|
| Bar Chart [Table] |
 | Best Quarter: 13.58% (12/31/22)
Worst Quarter: ‑23.19% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 6.80%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 13.58% (12/31/22)
Worst Quarter: -23.19% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 6.80%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
6.80%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
13.58%
|
| Highest Quarterly Return, Date |
Dec. 31, 2022
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(23.19%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of the Standard & Poor’s 500 Composite Stock Price Index (S&P 500 Index) (a broad-based securities market index), and three additional indexes with characteristics relevant to the Fund’s investment strategy. The Fund’s additional indexes are the MSCI USA Minimum Volatility Index (Net), the Russell 3000 Index, and the Fund’s blended benchmark that is composed of the MSCI USA Minimum Volatility Index (Net) and the Russell 3000 Value Index weighted 75%/25%.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
U.S. Managed Volatility Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(12/31/2008) |
Return Before Taxes | 10.75 | % | 10.02 | % | 9.66 | % | 11.61% |
Return After Taxes on Distributions | ‑3.06 | % | 4.22 | % | 5.60 | % | 8.11% |
Return After Taxes on Distributions and Sale of Fund Shares | 14.86 | % | 7.14 | % | 7.06 | % | 8.85% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 14.81% |
MSCI USA Minimum Volatility Index (Net) (reflects no deduction for fees,
expenses or taxes) | 7.31 | % | 8.01 | % | 9.92 | % | 11.55% |
Russell 3000 Index Return (reflects no deduction for fees, expenses or taxes) | 17.15 | % | 13.15 | % | 14.29 | % | 14.58% |
The Fund’s 75/25 Blended Benchmark Return (reflects no deduction for fees,
expenses or taxes) | 9.81 | % | 9.28 | % | 10.62 | % | 12.15% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| GLOBAL MANAGED VOLATILITY FUND | SIIT Global Managed Volatility Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past nine calendar years and by showing how the Fund’s average annual returns for 1 and 5 years and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on a full calendar year. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past nine calendar years and by showing how the Fund’s average annual returns for 1 and 5 years and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of the MSCI All Country World Ex-US Net Index (a broad-based securities market index), and two additional indexes with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 11.98% (12/31/22)
Worst Quarter: ‑20.50% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 8.35%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 11.98% (12/31/22)
Worst Quarter: -20.50% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 8.35%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
8.35%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
11.98%
|
| Highest Quarterly Return, Date |
Dec. 31, 2022
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(20.50%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of the MSCI All Country World Ex-US Net Index (a broad-based securities market index), and two additional indexes with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Global Managed Volatility Fund | 1 Year | 5 Years | Since
Inception
(1/29/2016) |
Return Before Taxes | 17.90 | % | 11.20 | % | 9.78 | % |
Return After Taxes on Distributions | 14.01 | % | 7.92 | % | 7.44 | % |
Return After Taxes on Distributions and Sale of Fund Shares | 12.92 | % | 8.07 | % | 7.28 | % |
MSCI All Country World Ex-US Net Index Return (reflects no deduction for
fees or expenses) | 32.39 | % | 7.91 | % | 9.26 | % |
MSCI World Index Return (reflects no deduction for fees or expenses) | 21.09 | % | 12.15 | % | 12.97 | % |
MSCI World Minimum Volatility Index (USD) Return (reflects no deduction for
fees or expenses) | 10.54 | % | 6.29 | % | 8.04 | % |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees or expenses)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| WORLD EQUITY EX-US FUND | SIIT WORLD EQUITY EX-US FUND |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Bar Chart [Table] |
 | Best Quarter: 19.84% (6/30/20)
Worst Quarter: ‑23.54% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 11.82%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 19.84% (6/30/20)
Worst Quarter: -23.54% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 11.82%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
11.82%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
19.84%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(23.54%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
World Equity Ex-US Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(3/28/2005) |
Return Before Taxes | 29.32 | % | 7.73 | % | 8.81 | % | 6.11% |
Return After Taxes on Distributions | 25.67 | % | 5.48 | % | 7.32 | % | 5.05% |
Return After Taxes on Distributions and Sale of Fund Shares | 19.70 | % | 5.68 | % | 6.89 | % | 4.83% |
MSCI All Country World Ex-US Net Index Return (reflects no deduction for
fees or expenses) | 32.39 | % | 7.91 | % | 8.41 | % | 6.21% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees or expenses)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| SCREENED WORLD EQUITY EX-US FUND | SIIT Screened World Equity Ex-US Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on a full calendar year. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Bar Chart [Table] |
 | Best Quarter: 19.32% (6/30/20)
Worst Quarter: ‑22.98% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 10.03%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 19.32% (6/30/20)
Worst Quarter: -22.98% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 10.03%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
10.03%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
19.32%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(22.98%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Screened World Equity Ex-US Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(6/30/2008) |
Return Before Taxes | 27.87 | % | 8.06 | % | 10.00 | % | 5.39% |
Return After Taxes on Distributions | 22.30 | % | 5.53 | % | 8.44 | % | 4.45% |
Return After Taxes on Distributions and Sale of Fund Shares | 19.42 | % | 5.88 | % | 7.95 | % | 4.28% |
MSCI All Country World Ex-US Net Index Return (reflects no deduction for
fees or expenses) | 32.39 | % | 7.91 | % | 8.41 | % | 4.75% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees or expenses)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| EMERGING MARKETS EQUITY FUND | SIIT EMERGING MARKETS EQUITY FUND |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risk of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception, compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risk of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception, compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 21.74% (6/30/20)
Worst Quarter: ‑25.81% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 22.28%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 21.74% (6/30/20)
Worst Quarter: -25.81% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 22.28%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
22.28%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
21.74%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(25.81%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Emerging Markets Equity Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(10/31/2014) |
Return Before Taxes | 39.81 | % | 9.20 | % | 10.14 | % | 7.29% |
Return After Taxes on Distributions | 31.12 | % | 6.40 | % | 8.20 | % | 5.55% |
Return After Taxes on Distributions and Sale of Fund Shares | 28.57 | % | 6.89 | % | 7.93 | % | 5.54% |
MSCI All Country World Ex-US Net Index Return (reflects no deduction for
fees or expenses) | 32.39 | % | 7.91 | % | 8.41 | % | 6.66% |
MSCI Emerging & Frontier Markets Index Return (reflects no deduction for
fees, expenses or taxes) | 33.78 | % | 4.26 | % | 8.39 | % | 5.38% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| OPPORTUNISTIC INCOME FUND | SIIT Opportunistic Income Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 6.68% (6/30/20)
Worst Quarter: ‑7.71% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 1.77%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 6.68% (6/30/20)
Worst Quarter: -7.71% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 1.77%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
1.77%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
6.68%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(7.71%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax
situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Opportunistic Income Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(12/14/2006) |
Return Before Taxes | 6.15 | % | 5.09 | % | 4.38 | % | 2.35% |
Return After Taxes on Distributions | 3.61 | % | 2.86 | % | 2.53 | % | 0.95% |
Return After Taxes on Distributions and Sale of Fund Shares | 3.60 | % | 2.92 | % | 2.54 | % | 1.16% |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deductions for
fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 3.17% |
ICE BofA USD 3-Month Deposit Offered Rate Constant Maturity Index Return
(reflects no deductions for fees, expenses or taxes) | 4.42 | % | 3.26 | % | 2.38 | % | 1.89% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deductions for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| CORE FIXED INCOME FUND | SIIT CORE FIXED INCOME |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Bar Chart [Table] |
 | Best Quarter: 7.31% (12/31/23)
Worst Quarter: ‑6.14% (3/31/22)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 0.64%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 7.31% (12/31/23)
Worst Quarter: -6.14% (3/31/22)
The Fund's total return from January 1, 2026 to June 30, 2026 was 0.64%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
0.64%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
7.31%
|
| Highest Quarterly Return, Date |
Dec. 31, 2023
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(6.14%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2022
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Core Fixed Income Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(6/14/1996) |
Return Before Taxes | 7.54 | % | ‑0.30 | % | 2.45 | % | 4.83% |
Return After Taxes on Distributions | 5.71 | % | ‑1.68 | % | 0.91 | % | 2.84% |
Return After Taxes on Distributions and Sale of Fund Shares | 4.44 | % | ‑0.83 | % | 1.22 | % | 2.94% |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deduction for
fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 4.37% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| HIGH YIELD BOND FUND | SIIT HIGH YIELD BOND FUND |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 9.47% (6/30/20)
Worst Quarter: ‑15.48% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 1.78%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 9.47% (6/30/20)
Worst Quarter: -15.48% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 1.78%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
1.78%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
9.47%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(15.48%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
High Yield Bond Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(12/5/2005) |
Return Before Taxes | 7.96 | % | 5.63 | % | 7.02 | % | 7.03% |
Return After Taxes on Distributions | 4.16 | % | 1.69 | % | 3.42 | % | 3.55% |
Return After Taxes on Distributions and Sale of Fund Shares | 4.64 | % | 2.52 | % | 3.78 | % | 3.87% |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deduction for
fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 3.30% |
ICE BofA U.S. High Yield Constrained Index Return (reflects no deduction for
fees, expenses or taxes) | 8.50 | % | 4.50 | % | 6.44 | % | 6.65% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| LONG DURATION FUND | SIIT LONG DURATION FUND |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of the Bloomberg U.S. Aggregate Bond Index (a broad-based securities market index) as well as a blended benchmark that is composed of the Bloomberg U.S. Long Credit Index and the Bloomberg U.S. Long Government Index weighted 70%/30%.
|
| Bar Chart [Table] |
 | Best Quarter: 12.96% (12/31/23)
Worst Quarter: ‑12.61% (6/30/22)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 0.85%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 12.96% (12/31/23)
Worst Quarter: -12.61% (6/30/22)
The Fund's total return from January 1, 2026 to June 30, 2026 was 0.85%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
0.85%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
12.96%
|
| Highest Quarterly Return, Date |
Dec. 31, 2023
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(12.61%)
|
| Lowest Quarterly Return, Date |
Jun. 30, 2022
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of the Bloomberg U.S. Aggregate Bond Index (a broad-based securities market index) as well as a blended benchmark that is composed of the Bloomberg U.S. Long Credit Index and the Bloomberg U.S. Long Government Index weighted 70%/30%.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Long Duration Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(4/21/2004) |
Return Before Taxes | 6.79 | % | ‑4.22 | % | 2.84 | % | 4.18% |
Return After Taxes on Distributions | 4.62 | % | ‑5.97 | % | 0.50 | % | 1.73% |
Return After Taxes on Distributions and Sale of Fund Shares | 3.99 | % | ‑3.80 | % | 1.33 | % | 2.30% |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deduction for
fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 3.29% |
The Fund’s 70/30 Blended Benchmark Return (reflects no deduction for
fees, expenses or taxes) | 7.13 | % | ‑4.18 | % | 2.43 | % | 4.68% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| LONG DURATION CREDIT FUND | SIIT Long Duration Credit Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception, compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception, compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 12.88% (12/31/23)
Worst Quarter: ‑11.97% (6/30/22)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 0.87%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 12.88% (12/31/23)
Worst Quarter: -11.97% (6/30/22)
The Fund's total return from January 1, 2026 to June 30, 2026 was 0.87%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
0.87%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
12.88%
|
| Highest Quarterly Return, Date |
Dec. 31, 2023
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(11.97%)
|
| Lowest Quarterly Return, Date |
Jun. 30, 2022
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Long Duration Credit Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(6/29/2012) |
Return Before Taxes | 7.36 | % | ‑3.67 | % | 2.92 | % | 3.21% |
Return After Taxes on Distributions | 5.18 | % | ‑5.49 | % | 0.96 | % | 1.19% |
Return After Taxes on Distributions and Sale of Fund Shares | 4.32 | % | ‑3.41 | % | 1.50 | % | 1.65% |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deductions for
fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 1.94% |
Bloomberg Long A+ U.S. Credit Index Return (reflects no deductions for
fees, expenses or taxes) | 7.54 | % | ‑3.69 | % | 2.59 | % | 2.78% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deductions for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| ULTRA SHORT DURATION BOND FUND | SIIT Ultra Short Duration Bond Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception, compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception, compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 2.63% (6/30/20)
Worst Quarter: ‑1.30% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 1.60%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 2.63% (6/30/20)
Worst Quarter: -1.30% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 1.60%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
1.60%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
2.63%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(1.30%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Ultra Short Duration Bond Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(2/28/2011) |
Return Before Taxes | 5.07 | % | 3.23 | % | 2.72 | % | 2.19% |
Return After Taxes on Distributions | 3.14 | % | 1.87 | % | 1.61 | % | 1.29% |
Return After Taxes on Distributions and Sale of Fund Shares | 2.98 | % | 1.88 | % | 1.60 | % | 1.29% |
Bloomberg U.S. Aggregate Bond Index Return (reflects no
deduction for fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 2.42% |
Bloomberg Short U.S. Treasury 9‑12 Month Index Return (reflects no
deduction for fees, expenses or taxes) | 4.40 | % | 2.78 | % | 2.18 | % | 1.55% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| EMERGING MARKETS DEBT FUND | SIIT EMERGING MARKETS DEBT FUND |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of the Bloomberg Global Aggregate Index (a broad-based securities market index) as well as a blended benchmark that is composed of the J.P. Morgan EMBI Global Diversified Index and the J.P. Morgan GBI-EM Global Diversified Index weighted 50%/50%.
|
| Bar Chart [Table] |
 | Best Quarter: 12.82% (6/30/20)
Worst Quarter: ‑16.50% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 4.48%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 12.82% (6/30/20)
Worst Quarter: -16.50% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 4.48%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
4.48%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
12.82%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(16.50%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of the Bloomberg Global Aggregate Index (a broad-based securities market index) as well as a blended benchmark that is composed of the J.P. Morgan EMBI Global Diversified Index and the J.P. Morgan GBI-EM Global Diversified Index weighted 50%/50%.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Emerging Markets Debt Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(12/5/2005) |
Return Before Taxes | 20.34 | % | 2.96 | % | 5.06 | % | 5.27% |
Return After Taxes on Distributions | 16.83 | % | 0.72 | % | 3.20 | % | 3.13% |
Return After Taxes on Distributions and Sale of Fund Shares | 11.96 | % | 1.22 | % | 3.08 | % | 3.22% |
Bloomberg Global Aggregate Index (USD) Return (reflects no deduction for
fees, expenses or taxes) | 8.17 | % | ‑2.15 | % | 1.26 | % | 2.55% |
The Fund’s Blended Benchmark Return (reflects no deduction for
fees, expenses or taxes) | 16.79 | % | 1.48 | % | 4.19 | % | 4.96% |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| REAL RETURN FUND | SIIT Real Return Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years, and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 3.51% (3/31/25)
Worst Quarter: ‑3.11% (9/30/22)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 1.43%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 3.51% (3/31/25)
Worst Quarter: -3.11% (9/30/22)
The Fund's total return from January 1, 2026 to June 30, 2026 was 1.43%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
1.43%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
3.51%
|
| Highest Quarterly Return, Date |
Mar. 31, 2025
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(3.11%)
|
| Lowest Quarterly Return, Date |
Sep. 30, 2022
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Real Return Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(12/14/2006) |
Return Before Taxes | 6.53 | % | 3.28 | % | 3.10 | % | 3.04 | % |
Return After Taxes on Distributions | 4.56 | % | 1.33 | % | 1.74 | % | 1.75 | % |
Return After Taxes on Distributions and Sale of Fund Shares | 3.85 | % | 1.65 | % | 1.79 | % | 1.83 | % |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deduction
for fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 3.17 | % |
Bloomberg 1‑5 Year U.S. TIPS Index Return (reflects no deduction
for fees, expenses or taxes) | 6.55 | % | 3.32 | % | 3.16 | % | 3.01 | % |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| LIMITED DURATION BOND FUND | SIIT Limited Duration Bond Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception, compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception, compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 3.05% (9/30/24)
Worst Quarter: ‑2.24% (3/31/22)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 1.04%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 3.05% (9/30/24)
Worst Quarter: -2.24% (3/31/22)
The Fund's total return from January 1, 2026 to June 30, 2026 was 1.04%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
1.04%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
3.05%
|
| Highest Quarterly Return, Date |
Sep. 30, 2024
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(2.24%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2022
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Limited Duration Bond Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(7/31/2014) |
Return Before Taxes | 5.87 | % | 2.43 | % | 2.49 | % | 2.25 | % |
Return After Taxes on Distributions | 4.01 | % | 1.12 | % | 1.38 | % | 1.22 | % |
Return After Taxes on Distributions and Sale of Fund Shares | 3.45 | % | 1.29 | % | 1.42 | % | 1.27 | % |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deduction
for fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 2.00 | % |
ICE BofA 1‑3 Year US Treasury Index Return (reflects no deduction
for fees, expenses or taxes) | 5.09 | % | 1.79 | % | 1.85 | % | 1.69 | % |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| INTERMEDIATE DURATION CREDIT FUND | SIIT Intermediate Duration Credit Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception compare with those of a broad measure of market performance. The performance information shown is based on full calendar years. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy.
|
| Bar Chart [Table] |
 | Best Quarter: 7.50% (12/31/23)
Worst Quarter: ‑7.03% (3/31/22)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 0.87%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 7.50% (12/31/23)
Worst Quarter: -7.03% (3/31/22)
The Fund's total return from January 1, 2026 to June 30, 2026 was 0.87%.
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
0.87%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
7.50%
|
| Highest Quarterly Return, Date |
Dec. 31, 2023
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(7.03%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2022
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of a broad-based securities market index and an additional index with characteristics relevant to the Fund’s investment strategy. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Intermediate Duration Credit Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(3/31/2015) |
Return Before Taxes | 7.39 | % | ‑0.19 | % | 3.01 | % | 2.60 | % |
Return After Taxes on Distributions | 5.38 | % | ‑1.79 | % | 1.48 | % | 1.10 | % |
Return After Taxes on Distributions and Sale of Fund Shares | 4.34 | % | ‑0.82 | % | 1.66 | % | 1.35 | % |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deductions
for fees, expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 1.77 | % |
Bloomberg A+ U.S. Credit Index Return (reflects no deductions
for fees, expenses or taxes) | 7.57 | % | ‑0.35 | % | 2.60 | % | 2.28 | % |
|
| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deductions for fees, expenses or taxes)
|
| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
|
| DYNAMIC ASSET ALLOCATION FUND | SIIT Dynamic Asset Allocation Fund |
|
| Prospectus [Line Items] |
|
| Bar Chart and Performance Table [Heading] |
Performance Information
|
| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception compare with those of a broad measure of market performance. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
|
| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
|
| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception compare with those of a broad measure of market performance.
|
| Bar Chart [Table] |
 | Best Quarter: 21.14% (6/30/20)
Worst Quarter: ‑19.08% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 8.68%.
|
|
| Bar Chart Closing [Text Block] |
Best Quarter: 21.14% (6/30/20)
Worst Quarter: -19.08% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 8.68%. |
|
| Year to Date Return, Label [Optional Text] |
total return
|
| Bar Chart, Year to Date Return |
8.68%
|
| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
|
| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
|
| Highest Quarterly Return |
21.14%
|
| Highest Quarterly Return, Date |
Jun. 30, 2020
|
| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
|
| Lowest Quarterly Return |
(19.08%)
|
| Lowest Quarterly Return, Date |
Mar. 31, 2020
|
| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
|
| Performance Table Narrative |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
|
| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
|
| Performance [Table] |
Dynamic Asset Allocation Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(7/30/2010) |
Return Before Taxes | 20.26 | % | 15.22 | % | 14.53 | % | 14.31% |
Return After Taxes on Distributions | 16.26 | % | 10.40 | % | 11.24 | % | 11.58% |
Return After Taxes on Distributions and Sale of Fund Shares | 14.01 | % | 10.84 | % | 11.08 | % | 11.28% |
S&P 500 Index Return (reflects no deduction for fees, expenses or taxes) | 17.88 | % | 14.42 | % | 14.82 | % | 14.69% |
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| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deduction for fees, expenses or taxes)
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| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
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| MULTI-ASSET REAL RETURN FUND | SIIT Multi-Asset Real Return Fund |
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| Prospectus [Line Items] |
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| Bar Chart and Performance Table [Heading] |
Performance Information
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| Performance Narrative [Text Block] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception, compare with those of a broad measure of market performance. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. For current performance information, please call 1‑800-DIAL-SEI.
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| Performance Past Does Not Indicate Future [Text] |
The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.
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| Performance Information Illustrates Variability of Returns [Text] |
The bar chart and the performance table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for the past ten calendar years, and by showing how the Fund’s average annual returns for 1, 5 and 10 years and since the Fund’s inception, compare with those of a broad measure of market performance.
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| Performance Additional Market Index [Text] |
This table compares the Fund’s average annual total returns to those of the Bloomberg U.S. Aggregate Bond Index (a broad-based securities market index) as well as a blended benchmark that is composed of the Bloomberg 1‑5 Year U.S. TIPS Index, the Bloomberg Commodity Total Return Index and the S&P 500 Index weighted 70%/20%/10%.
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| Bar Chart [Table] |
 | Best Quarter: 8.43% (3/31/22)
Worst Quarter: ‑9.92% (3/31/20)
The Fund’s total return from January 1, 2026 to June 30, 2026 was 5.40%.
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| Bar Chart Closing [Text Block] |
Best Quarter: 8.43% (3/31/22)
Worst Quarter: -9.92% (3/31/20)
The Fund's total return from January 1, 2026 to June 30, 2026 was 5.40%.
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| Year to Date Return, Label [Optional Text] |
total return
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| Bar Chart, Year to Date Return |
5.40%
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| Bar Chart, Year to Date Return, Date |
Jun. 30, 2026
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| Highest Quarterly Return, Label [Optional Text] |
Best Quarter:
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| Highest Quarterly Return |
8.43%
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| Highest Quarterly Return, Date |
Mar. 31, 2022
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| Lowest Quarterly Return, Label [Optional Text] |
Worst Quarter:
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| Lowest Quarterly Return |
(9.92%)
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| Lowest Quarterly Return, Date |
Mar. 31, 2020
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| Performance Table Heading |
Average Annual Total Returns (for the periods ended December 31, 2025)
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| Performance Table Narrative |
This table compares the Fund’s average annual total returns to those of the Bloomberg U.S. Aggregate Bond Index (a broad-based securities market index) as well as a blended benchmark that is composed of the Bloomberg 1‑5 Year U.S. TIPS Index, the Bloomberg Commodity Total Return Index and the S&P 500 Index weighted 70%/20%/10%.
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
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| Performance Table Uses Highest Federal Rate |
After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
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| Performance Table Not Relevant to Tax Deferred |
Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
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| Performance [Table] |
Multi-Asset Real Return Fund | 1 Year | 5 Years | 10 Years | Since
Inception
(7/28/2011) |
Return Before Taxes | 8.49 | % | 6.48 | % | 3.77 | % | 1.37% |
Return After Taxes on Distributions | 7.33 | % | 3.69 | % | 1.97 | % | 0.05% |
Return After Taxes on Distributions and Sale of Fund Shares | 5.13 | % | 3.81 | % | 2.14 | % | 0.47% |
Bloomberg U.S. Aggregate Bond Index Return (reflects no deductions for fees,
expenses or taxes) | 7.30 | % | ‑0.36 | % | 2.01 | % | 2.25% |
The Fund’s Blended Benchmark Return (reflects no deductions for fees,
expenses or taxes) | 9.57 | % | 6.04 | % | 4.99 | % | 2.58% |
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| Index No Deduction for Fees, Expenses, or Taxes [Text] |
(reflects no deductions for fees, expenses or taxes)
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| Performance Availability Phone [Text] |
1‑800-DIAL-SEI
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