Performance Management - Tandem Fund |
Nov. 01, 2026 |
|---|---|
| Prospectus [Line Items] | |
| Bar Chart and Performance Table [Heading] | Performance History |
| Performance Narrative [Text Block] | The bar chart and the 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 and by showing how the Fund’s average annual returns for the periods indicated 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. Updated performance information is available on the Fund's website at www.tiafunds.com or by calling 1-877-743-7820. |
| 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 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 and by showing how the Fund’s average annual returns for the periods indicated compare with those of a broad measure of market performance. |
| Bar Chart [Heading] | Annual Total Returns (calendar years ended 12/31) |
| Bar Chart Closing [Text Block] | For the period January 1, 2026 through September 30, 2026, the total return for the Fund was -10.88%.
Best Quarter (6/30/20) +12.94% Worst Quarter (3/31/20) -9.34% |
| Performance Table Heading | AVERAGE ANNUAL TOTAL RETURN FOR THE PERIODS ENDED 12/31/25 |
| Performance Table Uses Highest Federal Rate | After-tax returns are calculated using the historical highest marginal individual U.S. federal income tax rates and do not reflect the impact of state and local taxes. |
| Performance Table Not Relevant to Tax Deferred | Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and 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 Closing [Text Block] | After-tax returns are calculated using the historical highest marginal individual U.S. federal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and 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 Availability Website Address [Text] | www.tiafunds.com |
| Performance Availability Phone [Text] | 1-877-743-7820 |
| Tandem Fund Shares | |
| Prospectus [Line Items] | |
| Year to Date Return, Label [Optional Text] | total return for the Fund |
| Bar Chart, Year to Date Return | (10.88%) |
| Bar Chart, Year to Date Return, Date | Sep. 30, 2026 |
| Highest Quarterly Return, Label [Optional Text] | Best Quarter |
| Highest Quarterly Return | 12.94% |
| Highest Quarterly Return, Date | Jun. 30, 2020 |
| Lowest Quarterly Return, Label [Optional Text] | Worst Quarter |
| Lowest Quarterly Return | (9.34%) |
| Lowest Quarterly Return, Date | Mar. 31, 2020 |