| Form N-CSR Cover | 6 Months Ended |
| Oct. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| 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 | Oct. 31, 2024 |
| Shareholder Report | 6 Months Ended | |
| Oct. 31, 2024 USD ($) Holding | ||
| Shareholder Report [Line Items] | ||
| Document Type | N-CSRS | |
| 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 | Oct. 31, 2024 | |
| Multi-Manager Directional Alternative Strategies Fund - Institutional Class | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Multi-Manager Directional Alternative Strategies Fund | |
| Class Name | Institutional Class | |
| Trading Symbol | CDAZX | |
| Annual or Semi-Annual Statement [Text Block] | This semiannual shareholder report | |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at columbiathreadneedleus.com/resources/literature 1-800-345-6611. | |
| 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 $ 2.53 % (a) (a) Annualized. | |
| Expenses Paid, Amount | $ 134 | |
| Expense Ratio, Percent | 2.53% | [1] |
| Net Assets | $ 286,272,083 | |
| Holdings Count | Holding | 810 | |
| Investment Company, Portfolio Turnover | 127% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Fund net assets $ Total number of portfolio holdings 810 Portfolio turnover for the reporting period 127% | |
| 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 Equity Risk 48.1 % Short Equity Risk 47.8 % Asset Categories Equity Sector Allocation | |
| [1]Annualized. | ||
| Shareholder Report, Holdings (Details) - Multi-Manager Directional Alternative Strategies Fund - Institutional Class | Oct. 31, 2024 |
| Long Equity Risk [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 48.10% |
| Short Equity Risk [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 47.80% |
| Information Technology Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 17.40% |
| Healthcare Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15.30% |
| Industrial Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.60% |
| Financial Services Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.60% |
| Communications Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.90% |
| Unclassified Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 23.70% |
| Information Technology Sector One [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (17.40%) |
| Industrials Sector One [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (6.60%) |
| Consumer Discretionary Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (5.70%) |
| Health Care Sector One [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (5.60%) |
| Financials Sector One [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (4.30%) |
| Other Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (4.70%) |
| Common Stock [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 92.10% |
| Money Market Fund [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.60% |
| Other Issue Type [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| Other Issue Type Two [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (0.10%) |
| Exchange Traded Equity Funds [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (4.40%) |
| Common Stocks [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | (45.80%) |
