| Shareholder Report | 12 Months Ended |
| Jul. 31, 2024 USD ($) Holding Holdings |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Columbia Funds Series Trust I |
| Entity Central Index Key | 0000773757 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jul. 31, 2024 |
| Material Change Date | Aug. 01, 2024 |
| Columbia Tax-Exempt Fund (Class A) | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Tax-Exempt Fund |
| Class Name | Class A |
| Trading Symbol | COLTX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Tax-Exempt Fund (the Fund) for the period of August 1, 2023 to July 31, 2024. |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-800-345-6611 |
| Additional Information Website | columbiathreadneedleus.com/resources/literature |
| Expenses [Text Block] | What were the Fund costs for the reporting period? (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Class A $ 0.75 % |
| Expenses Paid, Amount | $ 77 |
| Expense Ratio, Percent | 0.75% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The performance of Class A shares for the period presented is shown in the Average Annual Total Returns table. Top Performance Contributors Allocations Security selection Treasury futures tur Top Performance Detractors Allocations Security selection |
| Performance Past Does Not Indicate Future [Text] | Past performance does not guarantee future performance. |
| Line Graph [Table Text Block] | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (%) 1 year 5 years 10 years Class A (excluding sales charges) 5.81 0.80 2.32 Class A (including sales charges) 2.65 0.19 2.00 Bloomberg Municipal Bond Index 3.74 1.18 2.47 |
| No Deduction of Taxes [Text Block] | Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares. |
| Updated Performance Information Location [Text Block] | Visit columbiathreadneedleus.com/investment-products/mutual-funds |
| Net Assets | $ 2,038,848,588 |
| Holdings Count | Holding | 484 |
| Advisory Fees Paid, Amount | $ 9,462,247 |
| Investment Company, Portfolio Turnover | 22% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 484 Management services fees $ Portfolio turnover for the reporting period 22% |
| Holdings [Text Block] | Graphical Representation of Fund The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change. Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest availab ngs a Top States/Territories Texas 12.7 % New York 9.4 % Illinois 9.1 % Pennsylvania 7.4 % Colorado 4.5 % New Jersey 4.2 % California 4.2 % Michigan 4.0 % Florida 3.1 % Puerto Rico 2.8 % Asset Categories Credit Quality |
| Credit Quality Explanation [Text Block] | Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest availab ngs a |
| Material Fund Change [Text Block] | On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect that the Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incremental income, futures (including interest rate and Treasury bond futures) to manage duration and hedge against changes in interest rates, and swaps, including Municipal Market Data Rate Locks (MMD Rate Locks) to manage duration and hedge against changes in interest rates. In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. These changes became effective on August 1, 2024. |
| Material Fund Change Strategies [Text Block] | On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect that the Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incremental income, futures (including interest rate and Treasury bond futures) to manage duration and hedge against changes in interest rates, and swaps, including Municipal Market Data Rate Locks (MMD Rate Locks) to manage duration and hedge against changes in interest rates. |
| Material Fund Change Risks Change [Text Block] | In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund dur columbiathreadneedleus.com/resources/literature |
| Updated Prospectus Phone Number | 1-800-345-6611 |
| Updated Prospectus Web Address | columbiathreadneedleus.com/resources/literature |
| Columbia Tax-Exempt Fund (Advisor Class) | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Tax-Exempt Fund |
| Class Name | Advisor Class |
| Trading Symbol | CTERX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Tax-Exempt Fund (the Fund) for the period of August 1, 2023 to July 31, 2024. |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-800-345-6611 |
| Additional Information Website | columbiathreadneedleus.com/resources/literature |
| Expenses [Text Block] | What were the Fund costs for the reporting period? (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Advisor Class $ 0.55 % |
| Expenses Paid, Amount | $ 57 |
| Expense Ratio, Percent | 0.55% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The performance of Advisor Class shares for the period presented is shown in the Average Annual Total Returns table. Top Performance Contributors Allocations Security selection Treasury futures Top Performance Detractors Allocations Security selection |
| Performance Past Does Not Indicate Future [Text] | Past performance does not guarantee future performance. |
| Line Graph [Table Text Block] | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (%) 1 year 5 years 10 years Advisor Class 6.02 1.00 2.52 Bloomberg Municipal Bond Index 3.74 1.18 2.47 |
| No Deduction of Taxes [Text Block] | Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares. |
| Material Change Date | Aug. 01, 2024 |
| Updated Performance Information Location [Text Block] | Visit columbiathreadneedleus.com/investment-products/mutual-funds |
| Net Assets | $ 2,038,848,588 |
| Holdings Count | Holdings | 484 |
| Advisory Fees Paid, Amount | $ 9,462,247 |
| Investment Company, Portfolio Turnover | 22% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 484 Managemen t ser $ Portfolio turnover for the reporting period 22% |
| Holdings [Text Block] | Graphical Representation of Fund The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change. Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily. Top States/Territories Texas 12.7 % New York 9.4 % Illinois 9.1 % Pennsylvania 7.4 % Colorado 4.5 % New Jersey 4.2 % California 4.2 % Michigan 4.0 % Florida 3.1 % Puerto Rico 2.8 % Asset Categories Credit Quality |
| Credit Quality Explanation [Text Block] | Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily. |
| Material Fund Change [Text Block] | On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect that the Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incrementa l inco |
| Material Fund Change Strategies [Text Block] | On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect that the Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incrementa l inco |
| Material Fund Change Risks Change [Text Block] | In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature |
| Updated Prospectus Phone Number | 1-800-345-6611 |
| Updated Prospectus Web Address | columbiathreadneedleus.com/resources/literature |
| Columbia Tax-Exempt Fund - Class C | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Tax-Exempt Fund |
| Class Name | Class C |
| Trading Symbol | COLCX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Tax-Exempt Fund (the Fund) for the period of August 1, 2023 to July 31, 2024. |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-800-345-6611 |
| Additional Information Website | columbiathreadneedleus.com/resources/literature |
| Expenses [Text Block] | What were the Fund costs for the reporting period? (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Class C $ 1.35 % |
| Expenses Paid, Amount | $ 138 |
| Expense Ratio, Percent | 1.35% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The performance of Class C shares for the period presented is shown in the Average Annual Total Returns table. Top Performance Contributors Allocations Security selection Treasury futures Top Performance Detractors Allocations Security selection |
| Performance Past Does Not Indicate Future [Text] | Past performance does not guarantee future performance. |
| Line Graph [Table Text Block] | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (%) 1 year 5 years 10 years Class C (excluding sales charges) 5.17 0.18 1.68 Class C (including sales charges) 4.17 0.18 1.68 Bloomberg Municipal Bond Index 3.74 1.18 2.47 |
| No Deduction of Taxes [Text Block] | Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares. |
| Material Change Date | Aug. 01, 2024 |
| Updated Performance Information Location [Text Block] | Visit columbiathreadneedleus.com/investment-products/mutual-funds |
| Net Assets | $ 2,038,848,588 |
| Holdings Count | Holdings | 484 |
| Advisory Fees Paid, Amount | $ 9,462,247 |
| Investment Company, Portfolio Turnover | 22% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 484 Management services fees $ Portfolio turnover for the reporting period 22% |
| Holdings [Text Block] | Graphical Representation The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change. Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned change Top States/Territories Texas 12.7 % New York 9.4 % Illinois 9.1 % Pennsylvania 7.4 % Colorado 4.5 % New Jersey 4.2 % California 4.2 % Michigan 4.0 % Florida 3.1 % Puerto Rico 2.8 % Asset Categories Credit Quality |
| Credit Quality Explanation [Text Block] | Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned change |
| Material Fund Change [Text Block] | Certain Fund Changes This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect that the Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incremental income, futures (including interest rate and Treasury bond futures) to manage duration and hedge against changes in interest rates, and swaps, including Municipal Market Data Rate Locks (MMD Rate Locks) to manage duration and hedge against changes in interest rates. In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. These changes became effective on August 1, 2024. |
| Material Fund Change Strategies [Text Block] | On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect that the Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incremental income, futures (including interest rate and Treasury bond futures) to manage duration and hedge against changes in interest rates, and swaps, including Municipal Market Data Rate Locks (MMD Rate Locks) to manage duration and hedge against changes in interest rates. |
| Material Fund Change Risks Change [Text Block] | In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature |
| Updated Prospectus Phone Number | 1-800-345-6611 |
| Updated Prospectus Web Address | columbiathreadneedleus.com/resources/literature |
| Columbia Tax-Exempt Fund - Institutional Class | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Tax-Exempt Fund |
| Class Name | Institutional Class |
| Trading Symbol | CTEZX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Tax-Exempt Fund (the Fund) for the period of August 1, 2023 to July 31, 2024. |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-800-345-6611 |
| Additional Information Website | columbiathreadneedleus.com/resources/literature |
| Expenses [Text Block] | What were the Fund costs for the reporting period? (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Institutional Class $ 0.55 % |
| Expenses Paid, Amount | $ 57 |
| Expense Ratio, Percent | 0.55% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The performance of Institutional Class shares for the period presented is shown in the Average Annual Total Returns table. Top Performance Contributors Allocations Security selection Treasury futures Top Performance Detractors Allocations Security selection |
| Performance Past Does Not Indicate Future [Text] | Past performance does not guarantee future performance. |
| Line Graph [Table Text Block] | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (%) 1 year 5 years 10 years Institutional Class 5.93 0.98 2.52 Bloomberg Municipal Bond Index 3.74 1.18 2.47 |
| No Deduction of Taxes [Text Block] | Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares. |
| Material Change Date | Aug. 01, 2024 |
| Updated Performance Information Location [Text Block] | Visit columbiathreadneedleus.com/investment-products/mutual-funds |
| Net Assets | $ 2,038,848,588 |
| Holdings Count | Holdings | 484 |
| Advisory Fees Paid, Amount | $ 9,462,247 |
| Investment Company, Portfolio Turnover | 22% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 484 Management services fees $ Portfolio turnover for the reporting period 22% |
| Holdings [Text Block] | Graphical Representation of Fund The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change. Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating Top States/Territories Texas 12.7 % New York 9.4 % Illinois 9.1 % Pennsylvania 7.4 % Colorado 4.5 % New Jersey 4.2 % California 4.2 % Michigan 4.0 % Florida 3.1 % Puerto Rico 2.8 % Asset Categories Credit Quality |
| Credit Quality Explanation [Text Block] | Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating |
| Material Fund Change [Text Block] | Certain Fund Changes This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect |
| Material Fund Change Strategies [Text Block] | On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect |
| Material Fund Change Risks Change [Text Block] | In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature |
| Updated Prospectus Phone Number | 1-800-345-6611 |
| Updated Prospectus Web Address | columbiathreadneedleus.com/resources/literature |
| Columbia Tax-Exempt Fund - Institutional 2 Class | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Tax-Exempt Fund |
| Class Name | Institutional 2 Class |
| Trading Symbol | CADMX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Tax-Exempt Fund (the Fund) for the period of August 1, 2023 to July 31, 2024. |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-800-345-6611 |
| Additional Information Website | columbiathreadneedleus.com/resources/literature |
| Expenses [Text Block] | What were the Fund costs for the reporting period? (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Institutional 2 Class $ 0.53 % |
| Expenses Paid, Amount | $ 55 |
| Expense Ratio, Percent | 0.53% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The performance of Institutional 2 Class shares for the period presented is shown in the Average Annual Total Returns table. Top Performance Contributors Allocations Security selection years Treasury futures Top Performance Detractors Allocations Security selection |
| Performance Past Does Not Indicate Future [Text] | Past performance does not guarantee future performance. |
| Line Graph [Table Text Block] | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (%) 1 year 5 years 10 years Institutional 2 Class 6.03 1.01 2.55 Bloomberg Municipal Bond Index 3.74 1.18 2.47 |
| No Deduction of Taxes [Text Block] | Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares. |
| Material Change Date | Aug. 01, 2024 |
| Updated Performance Information Location [Text Block] | Visit columbiathreadneedleus.com/investment-products/mutual-funds |
| Net Assets | $ 2,038,848,588 |
| Holdings Count | Holdings | 484 |
| Advisory Fees Paid, Amount | $ 9,462,247 |
| Investment Company, Portfolio Turnover | 22% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 484 Management services fees $ Portfolio turnover for the reporting period 22% |
| Holdings [Text Block] | Graphical Representation of Fund Holdings The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change. Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily. Top States/Territories Texas 12.7 % New York 9.4 % Illinois 9.1 % Pennsylvania 7.4 % Colorado 4.5 % New Jersey 4.2 % California 4.2 % Michigan 4.0 % Florida 3.1 % Puerto Rico 2.8 % Asset Categories Credit Quality |
| Credit Quality Explanation [Text Block] | Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily. |
| Material Fund Change [Text Block] | Certain Fund Changes This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment |
| Material Fund Change Strategies [Text Block] | On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment |
| Material Fund Change Risks Change [Text Block] | In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature |
| Updated Prospectus Phone Number | 1-800-345-6611 |
| Updated Prospectus Web Address | columbiathreadneedleus.com/resources/literature |
| Columbia Tax-Exempt Fund - Institutional 3 Class | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Tax-Exempt Fund |
| Class Name | Institutional 3 Class |
| Trading Symbol | CTEYX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Tax-Exempt Fund (the Fund) for the period of August 1, 2023 to July 31, 2024. |
| Shareholder Report Annual or Semi-Annual | annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611. |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1-800-345-6611 |
| Additional Information Website | columbiathreadneedleus.com/resources/literature |
| Expenses [Text Block] | What were the Fund costs for the reporting period? (Based on a hypothetical $10,000 investment) Class Cost of a $10,000 investment Cost paid as a percentage of a $10,000 investment Institutional 3 Class $ 0.49 % |
| Expenses Paid, Amount | $ 50 |
| Expense Ratio, Percent | 0.49% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The performance of Institutional 3 Class shares for the period presented is shown in the Average Annual Total Returns table. Top Performance Contributors Allocations Security selection Treasury futures performance Top Performance Detractors Allocations Security selection |
| Performance Past Does Not Indicate Future [Text] | Past performance does not guarantee future performance. |
| Line Graph [Table Text Block] | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (%) 1 year 5 years 10 years Institutional 3 Class (a) 6.08 1.07 2.51 Bloomberg Municipal Bond Index 3.74 1.18 2.47 (a) The returns shown for periods prior to March 1, 2017 (including returns for the Life of the Fund, if shown, which are since Fund inception) include the returns of Class A. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit columbiathreadneedleus.com/investor/investment-products/mutual-funds/appended-performance |
| No Deduction of Taxes [Text Block] | Performance does not reflect the deduction of taxes that a shareholder may pay on fund distributions or on the redemptions of fund shares. |
| Material Change Date | Aug. 01, 2024 |
| Updated Performance Information Location [Text Block] | Visit columbiathreadneedleus.com/investment-products/mutual-funds |
| Net Assets | $ 2,038,848,588 |
| Holdings Count | Holdings | 484 |
| Advisory Fees Paid, Amount | $ 9,462,247 |
| Investment Company, Portfolio Turnover | 22% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 484 Management services fees $ Portfolio turnover for the reporting period 22% |
| Holdings [Text Block] | Graphical Representation of Fund The tables below show the investment makeup of the Fund represented as a percentage of Fund net assets. Derivatives are excluded from the tables unless otherwise noted. The Fund's portfolio composition is subject to change. Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including Top States/Territories Texas 12.7 % New York 9.4 % Illinois 9.1 % Pennsylvania 7.4 % Colorado 4.5 % New Jersey 4.2 % California 4.2 % Michigan 4.0 % Florida 3.1 % Puerto Rico 2.8 % Asset Categories Credit Quality |
| Credit Quality Explanation [Text Block] | Bond ratings on Fund holdings are divided into categories ranging from highest to lowest credit quality, determined by using the middle rating of Moody’s, S&P and Fitch, after dropping the highest and lowest available ratings. When ratings are available from only two rating agencies, the lower rating is used. When a rating is available from only one rating agency, that rating is used. If a security is not rated by Moody's, S&P and Fitch, but has a rating by Kroll and/or DBRS, the same methodology is applied to those bonds that would otherwise be not rated. When a bond is not rated by any rating agency, it is designated as “Not rated.” Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including |
| Material Fund Change [Text Block] | Certain Fund Changes This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect that the Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incremental income, futures (including interest rate and Treasury bond futures) to manage duration and hedge against changes in interest rates, and swaps, including Municipal Market Data Rate Locks (MMD Rate Locks) to manage duration and hedge against changes in interest rates. In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. These changes became effective on August 1, 2024. |
| Material Fund Change Strategies [Text Block] | On July 26, 2024, the Fund supplemented its Prospectus’ Principal Investment Strategies to reflect that the Fund may enter into tender option bond (TOB) transactions and may invest in derivatives, such as floating rate municipal securities (floaters) and inverse floating rate municipal securities (inverse floaters) to add incremental income, futures (including interest rate and Treasury bond futures) to manage duration and hedge against changes in interest rates, and swaps, including Municipal Market Data Rate Locks (MMD Rate Locks) to manage duration and hedge against changes in interest rates. |
| Material Fund Change Risks Change [Text Block] | In addition, the Fund amended its Prospectus’ Principal Risks to include disclosure of the risks associated with investing in these instruments and derivatives generally. |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund during the reporting period. For more complete information, you may review the Fund’s prospectus, which is available at columbiathreadneedleus.com/resources/literature |
| Updated Prospectus Phone Number | 1-800-345-6611 |
| Updated Prospectus Web Address | columbiathreadneedleus.com/resources/literature |
