| Shareholder Report | 12 Months Ended |
| May 31, 2024 USD ($) 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 | May 31, 2024 |
| Columbia Adaptive Risk Allocation Fund (Class A) | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Adaptive Risk Allocation Fund |
| Class Name | Class A |
| Trading Symbol | CRAAX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Adaptive Risk Allocation Fund (the Fund) for the period of June 1, 2023 to May 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 |
| 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 Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $ 1.01 % |
| Expenses Paid, Amount | $ 106 |
| Expense Ratio, Percent | 1.01% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance Top Performance Contributors Tactical allocations Sector allocation Derivatives usage Top Performance Detractors Risk allocation |
| 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) 10.26 4.69 4.34 Class A (including sales charges) 3.88 3.45 3.73 Modified Blended Benchmark - 60% MSCI ACWI Index (Net), 40% Bloomberg Global Aggregate Index 14.03 6.41 5.01 Blended Benchmark - 60% MSCI ACWI Index (Net) Hedged to DM Currencies, 40% Bloomberg Global Aggregate Hedged USD Index 15.87 7.93 6.87 FTSE Three-Month U.S. Treasury Bill Index 5.61 2.17 1.48 MSCI ACWI (Net) 23.56 11.68 8.40 Bloomberg Global Aggregate Index 0.77 (1.62 ) (0.37 ) |
| 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 | $ 2,658,705,110 |
| Holdings Count | Holdings | 383 |
| Advisory Fees Paid, Amount | $ 21,348,501 |
| Investment Company, Portfolio Turnover | 190% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 383 Management services fees $ Portfolio turnover for the reporting period 190% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 28% |
| 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 su bje Derivative Exposure Long Credit Risk 30.0 % Equity Risk 50.7 % Foreign Exchange Risk 55.1 % Interest Rate Risk 17.7 % Short Equity Risk 10.1 % Foreign Exchange Risk 82.8 % Interest Rate Risk 4.9 % Asset Categories |
| Columbia Adaptive Risk Allocation Fund (Advisor Class) | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Adaptive Risk Allocation Fund |
| Class Name | Advisor Class |
| Trading Symbol | CARRX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Adaptive Risk Allocation Fund (the Fund) for the period of June 1, 2023 to May 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 |
| Additional Information Phone Number | 1-800-345-6611 |
| Additional Information Website | columbiathreadneedleus.com/resources/literature |
| Expenses [Text Block] | Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Advisor Class $ 0.76 % |
| Expenses Paid, Amount | $ 80 |
| Expense Ratio, Percent | 0.76% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance Top Performance Contributors Tactical allocations Sector allocation Derivatives usage Top Performance Detractors Risk allocation |
| 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 (a) 10.61 4.97 4.60 Modified Blended Benchmark - 60% MSCI ACWI Index (Net), 40% Bloomberg Global Aggregate Index 14.03 6.41 5.01 Blended Benchmark - 60% MSCI ACWI Index (Net) Hedged to DM Currencies, 40% Bloomberg Global Aggregate Hedged USD Index 15.87 7.93 6.87 FTSE Three-Month U.S. Treasury Bill Index 5.61 2.17 1.48 MSCI ACWI (Net) 23.56 11.68 8.40 Bloomberg Global Aggregate Index 0.77 (1.62 ) (0.37 ) (a) The returns shown for periods prior to October 1, 2014 (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 more |
| 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 | $ 2,658,705,110 |
| Holdings Count | Holdings | 383 |
| Advisory Fees Paid, Amount | $ 21,348,501 |
| Investment Company, Portfolio Turnover | 190% |
| Additional Fund Statistics [Text Block] | Fund net assets $ Total number of portfolio holdings 383 Management services fees $ Portfolio turnover for the reporting period 190% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 28% |
| 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. Derivative Exposure Long Credit Risk 30.0 % Equity Risk 50.7 % Foreign Exchange Risk 55.1 % Interest Rate Risk 17.7 % Short Equity Risk 10.1 % Foreign Exchange Risk 82.8 % Interest Rate Risk 4.9 % Asset Categories |
| Columbia Adaptive Risk Allocation Fund (Class C) | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Adaptive Risk Allocation Fund |
| Class Name | Class C |
| Trading Symbol | CRACX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Adaptive Risk Allocation Fund (the Fund) for the period of June 1, 2023 to May 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 |
| 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 Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C $ 1.76 % |
| Expenses Paid, Amount | $ 184 |
| Expense Ratio, Percent | 1.76% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance Top Performance Contributors Tactical allocations Sector allocation Derivatives usage Top Performance Detractors Risk allocation |
| 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) 9.36 3.91 3.57 Class C (including sales charges) 8.36 3.91 3.57 Modified Blended Benchmark - 60% MSCI ACWI Index (Net), 40% Bloomberg Global Aggregate Index 14.03 6.41 5.01 Blended Benchmark - 60% MSCI ACWI Index (Net) Hedged to DM Currencies, 40% Bloomberg Global Aggregate Hedged USD Index 15.87 7.93 6.87 FTSE Three-Month U.S. Treasury Bill Index 5.61 2.17 1.48 MSCI ACWI (Net) 23.56 11.68 8.40 Bloomberg Global Aggregate Index 0.77 (1.62 ) (0.37 ) |
| 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 | $ 2,658,705,110 |
| Holdings Count | Holdings | 383 |
| Advisory Fees Paid, Amount | $ 21,348,501 |
| Investment Company, Portfolio Turnover | 190% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 383 Management services fees $ Portfolio turnover for the reporting period 190% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 28% |
| 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. Derivative Exposure Long Credit Risk 30.0 % Equity Risk 50.7 % Foreign Exchange Risk 55.1 % Interest Rate Risk 17.7 % Short Equity Risk 10.1 % Foreign Exchange Risk 82.8 % Interest Rate Risk 4.9 % Asset Categories |
| Columbia Adaptive Risk Allocation Fund (Institutional 2 Class) | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Adaptive Risk Allocation Fund |
| Class Name | Institutional 2 Class |
| Trading Symbol | CRDRX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Adaptive Risk Allocation Fund (the Fund) for the period of June 1, 2023 to May 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 |
| 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 Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional 2 Class $ 0.77 % |
| Expenses Paid, Amount | $ 81 |
| Expense Ratio, Percent | 0.77% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance Top Performance Contributors Tactical allocations Sector allocation Derivatives usage Top Performance Detractors Risk allocation |
| 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 10.58 4.94 4.62 Modified Blended Benchmark - 60% MSCI ACWI Index (Net), 40% Bloomberg Global Aggregate Index 14.03 6.41 5.01 Blended Benchmark - 60% MSCI ACWI Index (Net) Hedged to DM Currencies, 40% Bloomberg Global Aggregate Hedged USD Index 15.87 7.93 6.87 FTSE Three-Month U.S. Treasury Bill Index 5.61 2.17 1.48 MSCI ACWI (Net) 23.56 11.68 8.40 Bloomberg Global Aggregate Index 0.77 (1.62 ) (0.37 ) |
| 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 | $ 2,658,705,110 |
| Holdings Count | Holdings | 383 |
| Advisory Fees Paid, Amount | $ 21,348,501 |
| Investment Company, Portfolio Turnover | 190% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 383 Management services fees $ Portfolio turnover for the reporting period 190% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 28% |
| 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. Derivative Exposure Long Credit Risk 30.0 % Equity Risk 50.7 % Foreign Exchange Risk 55.1 % Interest Rate Risk 17.7 % Short Equity Risk 10.1 % Foreign Exchange Risk 82.8 % Interest Rate Risk 4.9 % Asset Categories |
| Columbia Adaptive Risk Allocation Fund (Institutional Class) | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Adaptive Risk Allocation Fund |
| Class Name | Institutional Class |
| Trading Symbol | CRAZX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Adaptive Risk Allocation Fund (the Fund) for the period of June 1, 2023 to May 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 |
| 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 Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional Class $ 0.76 % |
| Expenses Paid, Amount | $ 80 |
| Expense Ratio, Percent | 0.76% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance Top Performance Contributors Tactical allocations Sector allocation Derivatives usage Top Performance Detractors Risk allocation |
| 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 10.63 4.96 4.61 Modified Blended Benchmark - 60% MSCI ACWI Index (Net), 40% Bloomberg Global Aggregate Index 14.03 6.41 5.01 Blended Benchmark - 60% MSCI ACWI Index (Net) Hedged to DM Currencies, 40% Bloomberg Global Aggregate Hedged USD Index 15.87 7.93 6.87 FTSE Three-Month U.S. Treasury Bill Index 5.61 2.17 1.48 MSCI ACWI (Net) 23.56 11.68 8.40 Bloomberg Global Aggregate Index 0.77 (1.62 ) (0.37 ) |
| 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 | $ 2,658,705,110 |
| Holdings Count | Holdings | 383 |
| Advisory Fees Paid, Amount | $ 21,348,501 |
| Investment Company, Portfolio Turnover | 190% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 383 Management services fees $ Portfolio turnover for the reporting period 190% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 28% |
| 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 Derivative Exposure Long Credit Risk 30.0 % Equity Risk 50.7 % Foreign Exchange Risk 55.1 % Interest Rate Risk 17.7 % Short Equity Risk 10.1 % Foreign Exchange Risk 82.8 % Interest Rate Risk 4.9 % Asset Categories |
| Columbia Adaptive Risk Allocation Fund (Institutional 3 Class) | |
| Shareholder Report [Line Items] | |
| Fund Name | Columbia Adaptive Risk Allocation Fund |
| Class Name | Institutional 3 Class |
| Trading Symbol | CARYX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Columbia Adaptive Risk Allocation Fund (the Fund) for the period of June 1, 2023 to May 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 |
| 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 Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional 3 Class $ 0.72 % |
| Expenses Paid, Amount | $ 76 |
| Expense Ratio, Percent | 0.72% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance Top Performance Contributors Tactical allocations Sector allocation Derivatives usage Top Performance Detractors Risk allocation |
| 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) 10.61 5.00 4.67 Modified Blended Benchmark - 60% MSCI ACWI Index (Net), 40% Bloomberg Global Aggregate Index 14.03 6.41 5.01 Blended Benchmark - 60% MSCI ACWI Index (Net) Hedged to DM Currencies, 40% Bloomberg Global Aggregate Hedged USD Index 15.87 7.93 6.87 FTSE Three-Month U.S. Treasury Bill Index 5.61 2.17 1.48 MSCI ACWI (Net) 23.56 11.68 8.40 Bloomberg Global Aggregate Index 0.77 (1.62 ) (0.37 ) (a) The returns shown for periods prior to October 1, 2014 (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. |
| Updated Performance Information Location [Text Block] | Visit columbiathreadneedleus.com/investment-products/mutual-funds |
| Net Assets | $ 2,658,705,110 |
| Holdings Count | Holdings | 383 |
| Advisory Fees Paid, Amount | $ 21,348,501 |
| Investment Company, Portfolio Turnover | 190% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 383 Management services fees $ Portfolio turnover for the reporting period 190% Portfolio turnover for the reporting period excluding to be announced (TBA) securities 28% |
| 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 Derivative Exposure Long Credit Risk 30.0 % Equity Risk 50.7 % Foreign Exchange Risk 55.1 % Interest Rate Risk 17.7 % Short Equity Risk 10.1 % Foreign Exchange Risk 82.8 % Interest Rate Risk 4.9 % Asset Categories |
