v3.26.3
Shareholder Report
 6 Months Ended
Jul. 31, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name SEI DAILY INCOME TRUST
Entity Central Index Key 0000701939
Entity Investment Company Type N-1A
Document Period End Date Jul. 31, 2026
C000018365  
Shareholder Report [Line Items]  
Fund Name Government Fund
Class Name Institutional Class Shares
Trading Symbol SEOXX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Institutional Class Shares of the Government Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Government Fund, Institutional Class Shares
$10
0.20%
Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.20%
AssetsNet $ 5,860,790,000
Holdings Count | Holding 157
Advisory Fees Paid, Amount $ 2,085
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
$5,860,790
157
$2,085
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
U.S. Government Agency Obligations
30.0%
Repurchase Agreements
30.5%
U.S. Treasury Obligations
32.3%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net Assets
BNP Paribas
3.640%
08/03/26
5.1%
FHLB
0.000%
09/16/26
4.6%
J.P. Morgan Securities
3.640%
08/03/26
3.4%
MUFG Securities Americas
3.640%
08/03/26
3.4%
Natixis S.A.
3.640%
08/03/26
3.4%
U.S. Treasury Bills
3.674%
09/03/26
3.2%
U.S. Treasury Bills
3.641%
08/11/26
3.1%
U.S. Treasury Bills
3.609%
08/20/26
2.8%
Goldman Sachs
3.640%
08/03/26
2.6%
Mizuho Securities
3.650%
08/03/26
2.6%
C000162326  
Shareholder Report [Line Items]  
Fund Name Government Fund
Class Name Admin Class Shares
Trading Symbol GFAXX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Admin Class Shares of the Government Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Government Fund, Admin Class Shares
$17
0.35%
Expenses Paid, Amount $ 17
Expense Ratio, Percent 0.35%
AssetsNet $ 5,860,790,000
Holdings Count | Holding 157
Advisory Fees Paid, Amount $ 2,085
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
$5,860,790
157
$2,085
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
U.S. Government Agency Obligations
30.0%
Repurchase Agreements
30.5%
U.S. Treasury Obligations
32.3%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net Assets
BNP Paribas
3.640%
08/03/26
5.1%
FHLB
0.000%
09/16/26
4.6%
J.P. Morgan Securities
3.640%
08/03/26
3.4%
MUFG Securities Americas
3.640%
08/03/26
3.4%
Natixis S.A.
3.640%
08/03/26
3.4%
U.S. Treasury Bills
3.674%
09/03/26
3.2%
U.S. Treasury Bills
3.641%
08/11/26
3.1%
U.S. Treasury Bills
3.609%
08/20/26
2.8%
Goldman Sachs
3.640%
08/03/26
2.6%
Mizuho Securities
3.650%
08/03/26
2.6%
C000240469  
Shareholder Report [Line Items]  
Fund Name Government Fund
Class Name Wealth Class Shares
Trading Symbol AABXX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Wealth Class Shares of the Government Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Government Fund, Wealth Class Shares
$17
0.35%
Expenses Paid, Amount $ 17
Expense Ratio, Percent 0.35%
AssetsNet $ 5,860,790,000
Holdings Count | Holding 157
Advisory Fees Paid, Amount $ 2,085
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
$5,860,790
157
$2,085
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
U.S. Government Agency Obligations
30.0%
Repurchase Agreements
30.5%
U.S. Treasury Obligations
32.3%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net Assets
BNP Paribas
3.640%
08/03/26
5.1%
FHLB
0.000%
09/16/26
4.6%
J.P. Morgan Securities
3.640%
08/03/26
3.4%
MUFG Securities Americas
3.640%
08/03/26
3.4%
Natixis S.A.
3.640%
08/03/26
3.4%
U.S. Treasury Bills
3.674%
09/03/26
3.2%
U.S. Treasury Bills
3.641%
08/11/26
3.1%
U.S. Treasury Bills
3.609%
08/20/26
2.8%
Goldman Sachs
3.640%
08/03/26
2.6%
Mizuho Securities
3.650%
08/03/26
2.6%
C000018374  
Shareholder Report [Line Items]  
Fund Name Government II Fund
Class Name Class F Shares
Trading Symbol TCGXX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Class F Shares of the Government II Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Government II Fund, Class F Shares
$10
0.20%
Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.20%
AssetsNet $ 1,035,538,000
Holdings Count | Holding 128
Advisory Fees Paid, Amount $ 265
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
$1,035,538
128
$265
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
U.S. Government Agency Obligations
30.3%
U.S. Treasury Obligations
70.0%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net Assets
U.S. Treasury Bills
3.635%
08/11/26
11.3%
U.S. Treasury Bills
3.626%
08/04/26
9.9%
U.S. Treasury Bills
3.618%
08/20/26
6.2%
FHLB
0.000%
09/16/26
5.0%
U.S. Treasury Bills
3.714%
09/03/26
4.8%
U.S. Treasury Bills
3.630%
08/25/26
4.8%
FHLB
0.000%
10/01/26
4.8%
U.S. Treasury Notes, USBMMY3M + 0.205%
4.057%
10/31/26
4.5%
U.S. Treasury Notes, USBMMY3M + 0.098%
3.950%
01/31/27
2.5%
U.S. Treasury Bills
3.564%
12/24/26
2.1%
C000018368  
Shareholder Report [Line Items]  
Fund Name Treasury II Fund
Class Name Class F Shares
Trading Symbol SCPXX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Class F Shares of the Treasury II Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Treasury II Fund, Class F Shares
$10
0.20%
Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.20%
AssetsNet $ 1,281,426,000
Holdings Count | Holding 51
Advisory Fees Paid, Amount $ 278
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
$1,281,426
51
$278
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
U.S. Treasury Obligations
106.5%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net Assets
U.S. Treasury Bills
3.635%
08/11/26
17.6%
U.S. Treasury Bills
3.638%
08/20/26
10.1%
U.S. Treasury Bills
3.714%
08/25/26
9.7%
U.S. Treasury Bills
3.683%
09/03/26
7.5%
U.S. Treasury Bills
2.037%
09/01/26
7.0%
U.S. Treasury Bills
3.613%
08/04/26
6.6%
U.S. Treasury Bills
3.671%
09/15/26
5.0%
U.S. Treasury Bills
3.632%
08/06/26
4.4%
U.S. Treasury Notes, USBMMY3M + 0.098%
3.950%
01/31/27
4.2%
U.S. Treasury Bills
0.000%
09/29/26
3.5%
C000022551  
Shareholder Report [Line Items]  
Fund Name Ultra Short Duration Bond Fund
Class Name Class F Shares
Trading Symbol SECPX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Class F Shares of the Ultra Short Duration Bond Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Ultra Short Duration Bond Fund, Class F Shares
$19
0.38%
Expenses Paid, Amount $ 19
Expense Ratio, Percent 0.38%
AssetsNet $ 205,261,000
Holdings Count | Holding 453
Advisory Fees Paid, Amount $ 97
InvestmentCompanyPortfolioTurnover 35.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
Portfolio Turnover Rate
$205,261
453
$97
35%
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
Futures Contracts
0.0%
Municipal Bonds
1.5%
Commercial Paper
1.8%
Repurchase Agreement
4.9%
U.S. Treasury Obligations
12.5%
Mortgage-Backed Securities
14.8%
Asset-Backed Securities
30.8%
Corporate Obligations
32.9%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net AssetsFootnote Reference(A)
U.S. Treasury Notes
3.625%
05/31/28
3.7%
U.S. Treasury Notes
3.500%
12/15/28
2.4%
U.S. Treasury Notes
4.250%
02/15/28
1.5%
U.S. Treasury Bills
3.935%
06/10/27
1.5%
U.S. Treasury Notes
4.000%
05/31/28
1.4%
U.S. Treasury Notes
3.375%
12/31/27
1.3%
Morgan Stanley, SOFR + 1.590%
5.164%
04/20/29
1.0%
JPMorgan Chase, SOFR + 0.765%
1.470%
09/22/27
0.9%
Synchrony Card Funding LLC, Ser 2024-A2, Cl A
4.930%
07/15/30
0.8%
American Express, SOFR + 0.581%
4.009%
02/09/29
0.8%
FootnoteDescription
Footnote(A)
Cash Equivalents and Repurchase Agreements are not shown in the top ten holdings.
C000158211  
Shareholder Report [Line Items]  
Fund Name Ultra Short Duration Bond Fund
Class Name Class Y Shares
Trading Symbol SECYX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Class Y Shares of the Ultra Short Duration Bond Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Ultra Short Duration Bond Fund, Class Y Shares
$15
0.30%
Expenses Paid, Amount $ 15
Expense Ratio, Percent 0.30%
AssetsNet $ 205,261,000
Holdings Count | Holding 453
Advisory Fees Paid, Amount $ 97
InvestmentCompanyPortfolioTurnover 35.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
Portfolio Turnover Rate
$205,261
453
$97
35%
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
Futures Contracts
0.0%
Municipal Bonds
1.5%
Commercial Paper
1.8%
Repurchase Agreement
4.9%
U.S. Treasury Obligations
12.5%
Mortgage-Backed Securities
14.8%
Asset-Backed Securities
30.8%
Corporate Obligations
32.9%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net AssetsFootnote Reference(A)
U.S. Treasury Notes
3.625%
05/31/28
3.7%
U.S. Treasury Notes
3.500%
12/15/28
2.4%
U.S. Treasury Notes
4.250%
02/15/28
1.5%
U.S. Treasury Bills
3.935%
06/10/27
1.5%
U.S. Treasury Notes
4.000%
05/31/28
1.4%
U.S. Treasury Notes
3.375%
12/31/27
1.3%
Morgan Stanley, SOFR + 1.590%
5.164%
04/20/29
1.0%
JPMorgan Chase, SOFR + 0.765%
1.470%
09/22/27
0.9%
Synchrony Card Funding LLC, Ser 2024-A2, Cl A
4.930%
07/15/30
0.8%
American Express, SOFR + 0.581%
4.009%
02/09/29
0.8%
FootnoteDescription
Footnote(A)
Cash Equivalents and Repurchase Agreements are not shown in the top ten holdings.
C000022552  
Shareholder Report [Line Items]  
Fund Name Short-Duration Government Fund
Class Name Class F Shares
Trading Symbol TCSGX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Class F Shares of the Short-Duration Government Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Short-Duration Government Fund, Class F Shares
$24
0.48%
Expenses Paid, Amount $ 24
Expense Ratio, Percent 0.48%
AssetsNet $ 587,824,000
Holdings Count | Holding 385
Advisory Fees Paid, Amount $ 283
InvestmentCompanyPortfolioTurnover 15.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
Portfolio Turnover Rate
$587,824
385
$283
15%
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
Futures Contracts
0.0%
Repurchase Agreement
5.8%
U.S. Treasury Obligations
27.5%
Mortgage-Backed Securities
70.0%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net AssetsFootnote Reference(A)
U.S. Treasury Notes
3.625%
08/31/27
8.0%
U.S. Treasury Notes
3.875%
07/15/28
7.9%
U.S. Treasury Notes
3.500%
10/15/28
5.6%
U.S. Treasury Notes
3.750%
04/15/28
4.0%
FNMA or FHLMC
5.500%
08/15/2041 - 08/15/2056
3.7%
FHLMC Multifamily Structured Pass-Through Certificates, Ser K516, Cl A2
5.477%
01/25/29
2.4%
U.S. Treasury Notes
3.625%
08/15/28
2.0%
Seasoned Loans Structured Transaction Trust, Ser 2023-1, Cl A12
3.250%
10/25/33
1.6%
GNMA, Ser 2022-87, Cl CA
2.500%
09/20/36
1.2%
FNMA REMIC, Ser 2024-41, Cl DA
5.500%
12/25/51
1.2%
FootnoteDescription
Footnote(A)
Repurchase Agreements are not shown in the top ten holdings.
C000147419  
Shareholder Report [Line Items]  
Fund Name Short-Duration Government Fund
Class Name Class Y Shares
Trading Symbol SDGFX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Class Y Shares of the Short-Duration Government Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Short-Duration Government Fund, Class Y Shares
$16
0.32%
Expenses Paid, Amount $ 16
Expense Ratio, Percent 0.32%
AssetsNet $ 587,824,000
Holdings Count | Holding 385
Advisory Fees Paid, Amount $ 283
InvestmentCompanyPortfolioTurnover 15.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
Portfolio Turnover Rate
$587,824
385
$283
15%
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
Futures Contracts
0.0%
Repurchase Agreement
5.8%
U.S. Treasury Obligations
27.5%
Mortgage-Backed Securities
70.0%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net AssetsFootnote Reference(A)
U.S. Treasury Notes
3.625%
08/31/27
8.0%
U.S. Treasury Notes
3.875%
07/15/28
7.9%
U.S. Treasury Notes
3.500%
10/15/28
5.6%
U.S. Treasury Notes
3.750%
04/15/28
4.0%
FNMA or FHLMC
5.500%
08/15/2041 - 08/15/2056
3.7%
FHLMC Multifamily Structured Pass-Through Certificates, Ser K516, Cl A2
5.477%
01/25/29
2.4%
U.S. Treasury Notes
3.625%
08/15/28
2.0%
Seasoned Loans Structured Transaction Trust, Ser 2023-1, Cl A12
3.250%
10/25/33
1.6%
GNMA, Ser 2022-87, Cl CA
2.500%
09/20/36
1.2%
FNMA REMIC, Ser 2024-41, Cl DA
5.500%
12/25/51
1.2%
FootnoteDescription
Footnote(A)
Repurchase Agreements are not shown in the top ten holdings.
C000022554  
Shareholder Report [Line Items]  
Fund Name GNMA Fund
Class Name Class F Shares
Trading Symbol SEGMX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Class F Shares of the GNMA Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
GNMA Fund, Class F Shares
$31
0.63%
Expenses Paid, Amount $ 31
Expense Ratio, Percent 0.63%
AssetsNet $ 9,620,000
Holdings Count | Holding 235
Advisory Fees Paid, Amount $ 5
InvestmentCompanyPortfolioTurnover 13.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
Portfolio Turnover Rate
$9,620
235
$5
13%
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
Futures Contracts
0.0%
Repurchase Agreement
3.1%
Mortgage-Backed Securities
99.5%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net AssetsFootnote Reference(A)
GNMA
2.000%
08/20/50
6.8%
GNMA
4.000%
09/20/42
4.9%
GNMA
3.000%
12/20/50
4.9%
GNMA
3.500%
06/20/47
3.7%
GNMA
2.000%
08/15/56
3.3%
GNMA
4.500%
01/20/46
3.3%
GNMA
2.500%
08/20/50
3.1%
GNMA, Ser 2016-136, Cl PJ
3.500%
01/20/46
3.0%
GNMA
2.500%
06/20/50
2.9%
GNMA
3.875%
05/15/42
2.4%
FootnoteDescription
Footnote(A)
Repurchase Agreements are not shown in the top ten holdings.
C000147421  
Shareholder Report [Line Items]  
Fund Name GNMA Fund
Class Name Class Y Shares
Trading Symbol SGMYX
Annual or Semi-Annual Statement [Text Block] Semi-Annual Shareholder Report
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] This semi-annual shareholder report contains important information about Class Y Shares of the GNMA Fund (the "Fund") for the period from February 1, 2026 to July 31, 2026. You can find additional information about the Fund at https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports. You can also request this information by contacting us at 610-676-1000.
Additional Information Phone Number 610-676-1000
Additional Information Website https://www.seic.com/mutual-fund-documentation/prospectuses-and-reports
Expenses [Text Block]

What were the Fund costs for the last six months?

(based on a hypothetical $10,000 investment) 

Table Summary
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
GNMA Fund, Class Y Shares
$19
0.38%
Expenses Paid, Amount $ 19
Expense Ratio, Percent 0.38%
AssetsNet $ 9,620,000
Holdings Count | Holding 235
Advisory Fees Paid, Amount $ 5
InvestmentCompanyPortfolioTurnover 13.00%
Additional Fund Statistics [Text Block]

Key Fund Statistics as of July 31, 2026

Table Summary
Total Net Assets (000's)
Number of Holdings
Total Advisory Fees Paid (000's)
Portfolio Turnover Rate
$9,620
235
$5
13%
Holdings [Text Block]

Asset/Sector WeightingsFootnote Reference*

Holdings Chart
Table Summary
Value
Value
Futures Contracts
0.0%
Repurchase Agreement
3.1%
Mortgage-Backed Securities
99.5%
FootnoteDescription
Footnote*
Percentages are calculated based on total net assets.
Largest Holdings [Text Block]

Top Ten Holdings

Table Summary
Holding Name
Coupon Rate
Maturity Date
Percentage of Total Net AssetsFootnote Reference(A)
GNMA
2.000%
08/20/50
6.8%
GNMA
4.000%
09/20/42
4.9%
GNMA
3.000%
12/20/50
4.9%
GNMA
3.500%
06/20/47
3.7%
GNMA
2.000%
08/15/56
3.3%
GNMA
4.500%
01/20/46
3.3%
GNMA
2.500%
08/20/50
3.1%
GNMA, Ser 2016-136, Cl PJ
3.500%
01/20/46
3.0%
GNMA
2.500%
06/20/50
2.9%
GNMA
3.875%
05/15/42
2.4%
FootnoteDescription
Footnote(A)
Repurchase Agreements are not shown in the top ten holdings.