XML 35 R2.htm IDEA: XBRL DOCUMENT v3.24.4
Shareholder Report
 12 Months Ended
Oct. 31, 2024
USD ($)
Holding
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 Oct. 31, 2024
Columbia Massachusetts Intermediate Municipal Bond Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Columbia Massachusetts Intermediate Municipal Bond Fund
Class Name Class A
Trading Symbol LMIAX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Massachusetts Intermediate Municipal Bond Fund (the Fund) for the period of November 1, 2023 to October 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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Class A
$
83		0.80
%
Expenses Paid, Amount $ 83
Expense Ratio, Percent 0.80%
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
| Positive contributions to the Fund’s performance relative to the benchmark were driven by the portfolio’s overweights to BBB, BB and non-rated bonds and continuing care retirement community (CCRC) bonds. An underweight to bonds with 2-6 years to maturity also added to benchmark relative performance.
Security selection
| Selection in special tax, continuing care retirement community (CCRC) and charter school bonds, bonds with 8-17 and 4-6 years to maturity, and bonds rated AA added to relative performance.
Top Performance Detractors
Allocations
| The Fund’s overweight to bonds with under two years to maturity detracted from performance relative to the benchmark.
Security selection
| Underweight positions in the financials sector detracted from relative performance.
Performance Past Does Not Indicate Future [Text] Past performance does not guarantee future performance.
Line Graph [Table Text Block] Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Class A (excluding sales charges)
(a)
7.25 0.32 1.34
Class A (including sales charges)
(a)
3.98 (0.29
)
1.03
Bloomberg 3-15 Year Blend Municipal Bond Index7.86 1.12 2.14
Bloomberg Municipal Bond Index9.70 1.05 2.30
(a)
Effective August 1, 2024, the Fund compares its performance to the Bloomberg Municipal Bond Index, a broad-based performance index that meets new regulatory requirements. The Fund’s performance is also compared to its prior benchmark, which more closely represents the market sectors and/or asset classes in which the Fund primarily invests.
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.
Performance Table Market Index Changed [Text Block] Effective August 1, 2024, the Fund compares its performance to the Bloomberg Municipal Bond Index, a broad-based performance index that meets new regulatory requirements.
Prior Market Index Comparison [Text Block] The Fund’s performance is also compared to its prior benchmark, which more closely represents the market sectors and/or asset classes in which the Fund primarily invests.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 83,466,698
Holdings Count | Holding 66
Advisory Fees Paid, Amount $ 433,912
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
83,466,698
Total number of portfolio holdings66
Management services fees
(represents 0.47% of Fund average net assets)
$
433,912
Portfolio turnover for the reporting period9%
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
Massachusetts Bay Transportation Authority
07/01/2032 0.000%		4.7
%
Massachusetts State College Building Authority
05/01/2028 0.000%		4.3
%
Commonwealth of Massachusetts
12/01/2030 5.000%		3.7
%
Massachusetts Development Finance Agency
07/01/2032 5.000%		3.4
%
Massachusetts Development Finance Agency
04/01/2034 5.000%		3.1
%
Massachusetts Bay Transportation Authority
07/01/2029 0.000%		3.1
%
Massachusetts Development Finance Agency
04/01/2035 5.000%		3.0
%
Massachusetts Clean Water Trust (The)
08/01/2038 5.000%		2.6
%
Massachusetts Transportation Trust Fund Metropolitan Highway System
01/01/2035 5.000%		2.6
%
Massachusetts Development Finance Agency
10/01/2037 4.000%		2.6
%
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
Massachusetts Bay Transportation Authority
07/01/2032 0.000%		4.7
%
Massachusetts State College Building Authority
05/01/2028 0.000%		4.3
%
Commonwealth of Massachusetts
12/01/2030 5.000%		3.7
%
Massachusetts Development Finance Agency
07/01/2032 5.000%		3.4
%
Massachusetts Development Finance Agency
04/01/2034 5.000%		3.1
%
Massachusetts Bay Transportation Authority
07/01/2029 0.000%		3.1
%
Massachusetts Development Finance Agency
04/01/2035 5.000%		3.0
%
Massachusetts Clean Water Trust (The)
08/01/2038 5.000%		2.6
%
Massachusetts Transportation Trust Fund Metropolitan Highway System
01/01/2035 5.000%		2.6
%
Massachusetts Development Finance Agency
10/01/2037 4.000%		2.6
%
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
or upon request at 1-800-345-6611.
Effective August 1, 2024, the Fund amended 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.
Material Fund Change Strategies [Text Block] Effective August 1, 2024, the Fund amended 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
or upon request at 1-800-345-6611.
Updated Prospectus Phone Number 1-800-345-6611
Updated Prospectus Web Address columbiathreadneedleus.com/resources/literature
Columbia Massachusetts Intermediate Municipal Bond Fund - Advisor Class  
Shareholder Report [Line Items]  
Fund Name Columbia Massachusetts Intermediate Municipal Bond Fund
Class Name Advisor Class
Trading Symbol CMANX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Massachusetts Intermediate Municipal Bond Fund (the Fund) for the period of November 1, 2023 to October 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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Advisor Class
$
57		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
| Positive contributions to the Fund’s performance relative to the benchmark were driven by the portfolio’s overweights to BBB, BB and non-rated bonds and continuing care retirement community (CCRC) bonds. An underweight to bonds with 2-6 years to maturity also added to benchmark relative performance.
Security selection
| Selection in special tax, continuing care retirement community (CCRC) and charter school bonds, bonds with 8-17 and 4-6 years to maturity, and bonds rated AA added to relative performance.
Top Performance Detractors
Allocations
| The Fund’s overweight to bonds with under two years to maturity detracted from performance relative to the benchmark.
Security selection
| Underweight positions in the financials sector detracted from relative performance.
Performance Past Does Not Indicate Future [Text] Past performance does not guarantee future performance.
Line Graph [Table Text Block] Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Advisor Class
(a)
7.530.571.58
Bloomberg 3-15 Year Blend Municipal Bond Index7.861.122.14
Bloomberg Municipal Bond Index9.701.052.30
(a)
Effective August 1, 2024, the Fund compares its performance to the Bloomberg Municipal Bond Index, a broad-based performance index that meets new regulatory requirements. The Fund’s performance is also compared to its prior benchmark, which more closely represents the market sectors and/or asset classes in which the Fund primarily invests.
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.
Performance Table Market Index Changed [Text Block] Effective August 1, 2024, the Fund compares its performance to the Bloomberg Municipal Bond Index, a broad-based performance index that meets new regulatory requirements.
Prior Market Index Comparison [Text Block] The Fund’s performance is also compared to its prior benchmark, which more closely represents the market sectors and/or asset classes in which the Fund primarily invests.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 83,466,698
Holdings Count | Holding 66
Advisory Fees Paid, Amount $ 433,912
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
83,466,698
Total number of portfolio holdings66
Management services fees
(represents 0.47% of Fund average net assets)
$
433,912
Portfolio turnover for the reporting period9%
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
Massachusetts Bay Transportation Authority
07/01/2032 0.000%		4.7
%
Massachusetts State College Building Authority
05/01/2028 0.000%		4.3
%
Commonwealth of Massachusetts
12/01/2030 5.000%		3.7
%
Massachusetts Development Finance Agency
07/01/2032 5.000%		3.4
%
Massachusetts Development Finance Agency
04/01/2034 5.000%		3.1
%
Massachusetts Bay Transportation Authority
07/01/2029 0.000%		3.1
%
Massachusetts Development Finance Agency
04/01/2035 5.000%		3.0
%
Massachusetts Clean Water Trust (The)
08/01/2038 5.000%		2.6
%
Massachusetts Transportation Trust Fund Metropolitan Highway System
01/01/2035 5.000%		2.6
%
Massachusetts Development Finance Agency
10/01/2037 4.000%		2.6
%
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
Massachusetts Bay Transportation Authority
07/01/2032 0.000%		4.7
%
Massachusetts State College Building Authority
05/01/2028 0.000%		4.3
%
Commonwealth of Massachusetts
12/01/2030 5.000%		3.7
%
Massachusetts Development Finance Agency
07/01/2032 5.000%		3.4
%
Massachusetts Development Finance Agency
04/01/2034 5.000%		3.1
%
Massachusetts Bay Transportation Authority
07/01/2029 0.000%		3.1
%
Massachusetts Development Finance Agency
04/01/2035 5.000%		3.0
%
Massachusetts Clean Water Trust (The)
08/01/2038 5.000%		2.6
%
Massachusetts Transportation Trust Fund Metropolitan Highway System
01/01/2035 5.000%		2.6
%
Massachusetts Development Finance Agency
10/01/2037 4.000%		2.6
%
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
or upon request at 1-800-345-6611.
Effective August 1, 2024, the Fund amended 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.
Material Fund Change Strategies [Text Block] Effective August 1, 2024, the Fund amended 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
or upon request at 1-800-345-6611.
Updated Prospectus Phone Number 1-800-345-6611
Updated Prospectus Web Address columbiathreadneedleus.com/resources/literature
Columbia Massachusetts Intermediate Municipal Bond Fund - Institutional Class  
Shareholder Report [Line Items]  
Fund Name Columbia Massachusetts Intermediate Municipal Bond Fund
Class Name Institutional Class
Trading Symbol SEMAX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Massachusetts Intermediate Municipal Bond Fund (the Fund) for the period of November 1, 2023 to October 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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Institutional Class
$
57		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
| Positive contributions to the Fund’s performance relative to the benchmark were driven by the portfolio’s overweights to BBB, BB and non-rated bonds and continuing care retirement community (CCRC) bonds. An underweight to bonds with 2-6 years to maturity also added to benchmark relative performance.
Security selection
| Selection in special tax, continuing care retirement community (CCRC) and charter school bonds, bonds with 8-17 and 4-6 years to maturity, and bonds rated AA added to relative performance.
Top Performance Detractors
Allocations
| The Fund’s overweight to bonds with under two years to maturity detracted from performance relative to the benchmark.
Security selection
| Underweight positions in the financials sector detracted from relative performance.
Performance Past Does Not Indicate Future [Text] Past performance does not guarantee future performance.
Line Graph [Table Text Block] Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Institutional Class
(a)
7.40 0.58 1.59
Bloomberg 3-15 Year Blend Municipal Bond Index7.86 1.12 2.14
Bloomberg Municipal Bond Index9.70 1.05 2.30
(a)
Effective August 1, 2024, the Fund compares its performance to the Bloomberg Municipal Bond Index, a broad-based performance index that meets new regulatory requirements. The Fund’s performance is also compared to its prior benchmark, which more closely represents the market sectors and/or asset classes in which the Fund primarily invests.
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.
Performance Table Market Index Changed [Text Block] Effective August 1, 2024, the Fund compares its performance to the Bloomberg Municipal Bond Index, a broad-based performance index that meets new regulatory requirements.
Prior Market Index Comparison [Text Block] The Fund’s performance is also compared to its prior benchmark, which more closely represents the market sectors and/or asset classes in which the Fund primarily invests.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 83,466,698
Holdings Count | Holding 66
Advisory Fees Paid, Amount $ 433,912
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
83,466,698
Total number of portfolio holdings66
Management services fees
(represents 0.47% of Fund average net assets)
$
433,912
Portfolio turnover for the reporting period9%
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
Massachusetts Bay Transportation Authority
07/01/2032 0.000%		4.7
%
Massachusetts State College Building Authority
05/01/2028 0.000%		4.3
%
Commonwealth of Massachusetts
12/01/2030 5.000%		3.7
%
Massachusetts Development Finance Agency
07/01/2032 5.000%		3.4
%
Massachusetts Development Finance Agency
04/01/2034 5.000%		3.1
%
Massachusetts Bay Transportation Authority
07/01/2029 0.000%		3.1
%
Massachusetts Development Finance Agency
04/01/2035 5.000%		3.0
%
Massachusetts Clean Water Trust (The)
08/01/2038 5.000%		2.6
%
Massachusetts Transportation Trust Fund Metropolitan Highway System
01/01/2035 5.000%		2.6
%
Massachusetts Development Finance Agency
10/01/2037 4.000%		2.6
%
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
Massachusetts Bay Transportation Authority
07/01/2032 0.000%		4.7
%
Massachusetts State College Building Authority
05/01/2028 0.000%		4.3
%
Commonwealth of Massachusetts
12/01/2030 5.000%		3.7
%
Massachusetts Development Finance Agency
07/01/2032 5.000%		3.4
%
Massachusetts Development Finance Agency
04/01/2034 5.000%		3.1
%
Massachusetts Bay Transportation Authority
07/01/2029 0.000%		3.1
%
Massachusetts Development Finance Agency
04/01/2035 5.000%		3.0
%
Massachusetts Clean Water Trust (The)
08/01/2038 5.000%		2.6
%
Massachusetts Transportation Trust Fund Metropolitan Highway System
01/01/2035 5.000%		2.6
%
Massachusetts Development Finance Agency
10/01/2037 4.000%		2.6
%
Material Fund Change [Text Block]
Certain Fund
Chang
es
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
or upon request at 1-800-345-6611.
Effective August 1, 2024, the Fund amended 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.
Material Fund Change Strategies [Text Block] Effective August 1, 2024, the Fund amended 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
or upon request at 1-800-345-6611.
Updated Prospectus Phone Number 1-800-345-6611
Updated Prospectus Web Address columbiathreadneedleus.com/resources/literature
Columbia Massachusetts Intermediate Municipal Bond Fund - Institutional 3 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Massachusetts Intermediate Municipal Bond Fund
Class Name Institutional 3 Class
Trading Symbol CMMYX
Annual or Semi-Annual Statement [Text Block] This annual shareholder report contains important information about Columbia Massachusetts Intermediate Municipal Bond Fund (the Fund) for the period of November 1, 2023 to October 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
. You can also request more information by contacting us at
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)
ClassCost of a $10,000 investmentCost paid as a percentage of a $10,000 investment
Institutional 3 Class
$
47		0.45
%
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.45%
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
| Positive contributions to the Fund’s performance relative to the benchmark were driven by the portfolio’s overweights to BBB, BB and non-rated bonds and continuing care retirement community (CCRC) bonds. An underweight to bonds with 2-6 years to maturity also added to benchmark relative performance.
Security selection
| Selection in special tax, continuing care retirement community (CCRC) and charter school bonds, bonds with 8-17 and 4-6 years to maturity, and bonds rated AA added to relative performance.
Top Performance Detractors
Allocations
| The Fund’s overweight to bonds with under two years to maturity detracted from performance relative to the benchmark.
Security selection
| Underweight positions in the financials sector detracted from relative
performance
.
Performance Past Does Not Indicate Future [Text] Past performance does not guarantee future performance.
Line Graph [Table Text Block] Fund Performance - Growth of 10K
Average Annual Return [Table Text Block]
Average Annual Total Returns (%)1 year5 years10 years
Institutional 3 Class
(a),(b)
7.59 0.68 1.67
Bloomberg 3-15 Year Blend Municipal Bond Index7.86 1.12 2.14
Bloomberg Municipal Bond Index9.70 1.05 2.30
(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 Institutional Class. 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
for more information.
(b)
Effective August 1, 2024, the Fund compares its performance to the Bloomberg Municipal Bond Index, a broad-based performance index that meets new regulatory requirements. The Fund’s performance is also compared to its prior benchmark, which more closely represents the market sectors and/or asset classes in which the Fund primarily invests.
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.
Performance Table Market Index Changed [Text Block] Effective August 1, 2024, the Fund compares its performance to the Bloomberg Municipal Bond Index, a broad-based performance index that meets new regulatory requirements.
Prior Market Index Comparison [Text Block] The Fund’s performance is also compared to its prior benchmark, which more closely represents the market sectors and/or asset classes in which the Fund primarily invests.
Updated Performance Information Location [Text Block] Visit
columbiathreadneedleus.com/investment-products/mutual-funds
for more recent performance information.
Net Assets $ 83,466,698
Holdings Count | Holding 66
Advisory Fees Paid, Amount $ 433,912
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
83,466,698
Total number of portfolio holdings66
Management services fees
(represents 0.47% of Fund average net assets)
$
433,912
Portfolio turnover for the reporting period9%
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
Massachusetts Bay Transportation Authority
07/01/2032 0.000%		4.7
%
Massachusetts State College Building Authority
05/01/2028 0.000%		4.3
%
Commonwealth of Massachusetts
12/01/2030 5.000%		3.7
%
Massachusetts Development Finance Agency
07/01/2032 5.000%		3.4
%
Massachusetts Development Finance Agency
04/01/2034 5.000%		3.1
%
Massachusetts Bay Transportation Authority
07/01/2029 0.000%		3.1
%
Massachusetts Development Finance Agency
04/01/2035 5.000%		3.0
%
Massachusetts Clean Water Trust (The)
08/01/2038 5.000%		2.6
%
Massachusetts Transportation Trust Fund Metropolitan Highway System
01/01/2035 5.000%		2.6
%
Massachusetts Development Finance Agency
10/01/2037 4.000%		2.6
%
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
Massachusetts Bay Transportation Authority
07/01/2032 0.000%		4.7
%
Massachusetts State College Building Authority
05/01/2028 0.000%		4.3
%
Commonwealth of Massachusetts
12/01/2030 5.000%		3.7
%
Massachusetts Development Finance Agency
07/01/2032 5.000%		3.4
%
Massachusetts Development Finance Agency
04/01/2034 5.000%		3.1
%
Massachusetts Bay Transportation Authority
07/01/2029 0.000%		3.1
%
Massachusetts Development Finance Agency
04/01/2035 5.000%		3.0
%
Massachusetts Clean Water Trust (The)
08/01/2038 5.000%		2.6
%
Massachusetts Transportation Trust Fund Metropolitan Highway System
01/01/2035 5.000%		2.6
%
Massachusetts Development Finance Agency
10/01/2037 4.000%		2.6
%
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
or upon request at 1-800-345-6611.
Effective August 1, 2024, the Fund amended 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.
Material Fund Change Strategies [Text Block] Effective August 1, 2024, the Fund amended 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
or upon request at 1-800-345-6611.
Updated Prospectus Phone Number 1-800-345-6611
Updated Prospectus Web Address columbiathreadneedleus.com/resources/literature