v3.25.2
Shareholder Report
 6 Months Ended
Apr. 30, 2025
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 Apr. 30, 2025
Columbia Strategic New York Municipal Income Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Columbia Strategic New York Municipal Income Fund
Class Name Class A
Trading Symbol COLNX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Strategic New York Municipal Income Fund (the Fund) for the period of November 1, 2024 to April 30, 2025.
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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Class A
$
37		0.76
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.76% [1]
Net Assets $ 117,120,890
Holdings Count | Holding 101
Investment Company, Portfolio Turnover 5.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
117,120,890
Total number of portfolio holdings101
Portfolio turnover for the reporting period5%
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 Ratings, 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 Ratings, S&P or 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 Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
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 Ratings, 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 Ratings, S&P or 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.
Largest Holdings [Text Block]
Top Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Columbia Strategic New York Municipal Income Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Columbia Strategic New York Municipal Income Fund
Class Name Class C
Trading Symbol CNYCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Strategic New York Municipal Income Fund (the Fund) for the period of November 1, 2024 to April 30, 2025.
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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Class C
$
59		1.21
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 59
Expense Ratio, Percent 1.21% [1]
Net Assets $ 117,120,890
Holdings Count | Holding 101
Investment Company, Portfolio Turnover 5.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
117,120,890
Total number of portfolio holdings101
Portfolio turnover for the reporting period5%
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 Ratings, 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 Ratings, S&P or 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 Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
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 Ratings, 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 Ratings, S&P or 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.
Largest Holdings [Text Block]
Top Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Columbia Strategic New York Municipal Income Fund - Institutional Class  
Shareholder Report [Line Items]  
Fund Name Columbia Strategic New York Municipal Income Fund
Class Name Institutional Class
Trading Symbol CNYZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Strategic New York Municipal Income Fund (the Fund) for the period of November 1, 2024 to April 30, 2025.
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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Institutional Class
$
25		0.51
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.51% [1]
Net Assets $ 117,120,890
Holdings Count | Holding 101
Investment Company, Portfolio Turnover 5.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
117,120,890
Total number of portfolio holdings101
Portfolio turnover for the reporting period5%
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 Ratings, 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 Ratings, S&P or 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 Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
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 Ratings, 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 Ratings, S&P or 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.
Largest Holdings [Text Block]
Top Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Columbia Strategic New York Municipal Income Fund - Institutional 2 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Strategic New York Municipal Income Fund
Class Name Institutional 2 Class
Trading Symbol CNYRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Strategic New York Municipal Income Fund (the Fund) for the period of November 1, 2024 to April 30, 2025.
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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Institutional 2 Class
$
24		0.49
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 24
Expense Ratio, Percent 0.49% [1]
Net Assets $ 117,120,890
Holdings Count | Holding 101
Investment Company, Portfolio Turnover 5.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
117,120,890
Total number of portfolio holdings101
Portfolio turnover for the reporting period5%
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 Ratings, 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 Ratings, S&P or 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 Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
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 Ratings, 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 Ratings, S&P or 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.
Largest Holdings [Text Block]
Top Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Columbia Strategic New York Municipal Income Fund - Institutional 3 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Strategic New York Municipal Income Fund
Class Name Institutional 3 Class
Trading Symbol CNTYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Strategic New York Municipal Income Fund (the Fund) for the period of November 1, 2024 to April 30, 2025.
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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Institutional 3 Class
$
22		0.44
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 22
Expense Ratio, Percent 0.44% [1]
Net Assets $ 117,120,890
Holdings Count | Holding 101
Investment Company, Portfolio Turnover 5.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
117,120,890
Total number of portfolio holdings101
Portfolio turnover for the reporting period5%
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 Ratings, 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 Ratings, S&P or 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 Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Credit Quality
Graphical Representation - Allocation 2 Chart
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 Ratings, 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 Ratings, S&P or 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.
Largest Holdings [Text Block]
Top Holdings
New York City Municipal Water Finance Authority
06/15/2054 5.250%		2.7
%
Triborough Bridge & Tunnel Authority
05/15/2064 5.250%		2.7
%
New York Transportation Development Corp.
06/30/2060 5.375%		2.6
%
TSASC, Inc.
06/01/2041 5.000%		2.5
%
New York City Transitional Finance Authority
08/01/2048 4.000%		2.3
%
New York State Dormitory Authority
03/15/2054 4.000%		2.3
%
City of New York
09/01/2046 4.000%		2.3
%
Triborough Bridge & Tunnel Authority
05/15/2062 5.250%		2.2
%
Port Authority of New York & New Jersey
06/01/2094 6.125%		1.9
%
Triborough Bridge & Tunnel Authority
05/15/2063 5.500%		1.8
%
[1] Annualized.