S000031375 [Member] Investment Strategy - Columbia Select Small Cap Value Fund	May 31, 2025
Prospectus [Line Items]
Strategy [Heading]	Principal Investment Strategies
Strategy Narrative [Text Block]	Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in equity securities of small capitalization issuers. These companies have market capitalizations in the range of companies in the Russell 2000® Value Index (the Index) at the time of purchase (between $31.6 million and $10.9 billion as of August 31, 2025). The market capitalization range and composition of companies in the Index are subject to change. The Fund’s Board of Trustees may change the parameters by which smaller market capitalization is defined if it concludes such a change is appropriate. The Fund invests substantially in securities of U.S. issuers. The Fund may invest up to 25% of its net assets in foreign investments. The Fund also invests substantially in “value” companies. The Fund considers “value” companies to be those companies believed by the investment manager to be undervalued, either historically, by the market, or as compared with issuers in the same or similar industry or sector. The Fund may at times emphasize one or more sectors in selecting its investments, including the financials sector. The Fund also may invest in real estate investment trusts. The Fund may hold a small number of securities, consistent with its value investment approach. Generally, the Fund anticipates holding between 45 and 55 securities in its portfolio; however, the Fund may hold, at any time, more or fewer securities than noted in this range.

Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in equity securities of small capitalization issuers. These companies have market capitalizations in the range of companies in the Russell 2000® Value Index (the Index) at the time of purchase (between $31.6 million and $10.9 billion as of August 31, 2025). The market capitalization range and composition of companies in the Index are subject to change. The Fund’s Board of Trustees may change the parameters by which smaller market capitalization is defined if it concludes such a change is appropriate.

The Fund invests substantially in securities of U.S. issuers. The Fund may invest up to 25% of its net assets in foreign investments. The Fund also invests substantially in “value” companies. The Fund considers “value” companies to be those companies believed by the investment manager to be undervalued, either historically, by the market, or as compared with issuers in the same or similar industry or sector. The Fund may at times emphasize one or more sectors in selecting its investments, including the financials sector. The Fund also may invest in real estate investment trusts. The Fund may hold a small number of securities, consistent with its value investment approach. Generally, the Fund anticipates holding between 45 and 55 securities in its portfolio; however, the Fund may hold, at any time, more or fewer securities than noted in this range.