v3.25.2
Shareholder Report
 6 Months Ended
Jun. 30, 2025
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Columbia Acorn Trust
Entity Central Index Key 0000002110
Entity Investment Company Type N-1A
Document Period End Date Jun. 30, 2025
Columbia Acorn® Fund - Class A  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn® Fund
Class Name Class A
Trading Symbol LACAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn
®
Fund (the Fund) for the period of January 1, 2025 to June 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
$
51		1.05
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 51
Expense Ratio, Percent 1.05% [1]
Net Assets $ 2,461,733,489
Holdings Count | Holding 100
Investment Company, Portfolio Turnover 43.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,461,733,489
Total number of portfolio holdings
100
Portfolio turnover for the reporting period
43%
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.
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Equity Sector Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Columbia Acorn® Fund - Class C  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn® Fund
Class Name Class C
Trading Symbol LIACX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn
®
Fund (the Fund) for the period of January 1, 2025 to June 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
$
87		1.80
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 87
Expense Ratio, Percent 1.80% [1]
Net Assets $ 2,461,733,489
Holdings Count | Holding 100
Investment Company, Portfolio Turnover 43.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,461,733,489
Total number of portfolio holdings
100
Portfolio turnover for the reporting period
43%
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.
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Equity Sector Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Columbia Acorn® Fund - Institutional Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn® Fund
Class Name Institutional Class
Trading Symbol ACRNX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn
®
Fund (the Fund) for the period of January 1, 2025 to June 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
$
39		0.80
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 39
Expense Ratio, Percent 0.80% [1]
Net Assets $ 2,461,733,489
Holdings Count | Holding 100
Investment Company, Portfolio Turnover 43.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,461,733,489
Total number of portfolio holdings
100
Portfolio turnover for the reporting period
43%
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.
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Equity Sector Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Columbia Acorn® Fund - Institutional 2 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn® Fund
Class Name Institutional 2 Class
Trading Symbol CRBRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn
®
Fund (the Fund) for the period of January 1, 2025 to June 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
$
37		0.77
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 37
Expense Ratio, Percent 0.77% [1]
Net Assets $ 2,461,733,489
Holdings Count | Holding 100
Investment Company, Portfolio Turnover 43.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,461,733,489
Total number of portfolio holdings
100
Portfolio turnover for the reporting period
43%
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.
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Equity Sector Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Columbia Acorn® Fund - Institutional 3 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn® Fund
Class Name Institutional 3 Class
Trading Symbol CRBYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn
®
Fund (the Fund) for the period of January 1, 2025 to June 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
$
35		0.72
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 35
Expense Ratio, Percent 0.72% [1]
Net Assets $ 2,461,733,489
Holdings Count | Holding 100
Investment Company, Portfolio Turnover 43.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,461,733,489
Total number of portfolio holdings
100
Portfolio turnover for the reporting period
43%
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.
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Equity Sector Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Columbia Acorn® Fund - Class S  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn® Fund
Class Name Class S
Trading Symbol ACRSX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn
®
Fund (the Fund) for the period of January 1, 2025 to June 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 S
$
39		0.80
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 39
Expense Ratio, Percent 0.80% [1]
Net Assets $ 2,461,733,489
Holdings Count | Holding 100
Investment Company, Portfolio Turnover 43.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
2,461,733,489
Total number of portfolio holdings
100
Portfolio turnover for the reporting period
43%
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.
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Equity Sector Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
SPX Technologies, Inc.2.6
%
Churchill Downs, Inc.2.4
%
GCM Grosvenor, Inc., Class A2.4
%
Parsons Corp.2.4
%
Curtiss-Wright Corp.2.3
%
Wingstop, Inc.2.2
%
Five Below, Inc.2.2
%
Carlyle Group, Inc. (The)2.1
%
HealthEquity, Inc.2.1
%
Colliers International Group, Inc.2.1
%
Columbia Acorn International® - Class A  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International®
Class Name Class A
Trading Symbol LAIAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International
®
(the Fund) for the period of January 1, 2025 to June 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
$
66		1.22
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 66
Expense Ratio, Percent 1.22% [1]
Net Assets $ 925,680,060
Holdings Count | Holding 67
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
925,680,060
Total number of portfolio holdings
67
Portfolio turnover for the reporting period
9%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the inv
es
tment 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.
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR Group Ltd.2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR Group Ltd.2.3
%
Columbia Acorn International® - Institutional Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International®
Class Name Institutional Class
Trading Symbol ACINX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International
®
(the Fund) for the period of January 1, 2025 to June 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
$
52		0.96
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 52
Expense Ratio, Percent 0.96% [1]
Net Assets $ 925,680,060
Holdings Count | Holding 67
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
925,680,060
Total number of portfolio holdings
67
Portfolio turnover for the reporting period
9%
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.
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR Group Ltd.2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR Group Ltd.2.3
%
Columbia Acorn International® - Institutional 2 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International®
Class Name Institutional 2 Class
Trading Symbol CAIRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International
®
(the Fund) for the period of January 1, 2025 to June 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
$
48		0.90
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.90% [1]
Net Assets $ 925,680,060
Holdings Count | Holding 67
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key
Fund
Statistics
Fund net assets
$
925,680,060
Total number of portfolio holdings
67
Portfolio turnover for the reporting period
9%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdin
gs
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.
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR
Group
Ltd.		2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR
Group
Ltd.		2.3
%
Columbia Acorn International® - Institutional 3 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International®
Class Name Institutional 3 Class
Trading Symbol CCYIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International
®
(the Fund) for the period of January 1, 2025 to June 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
$
46		0.85
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 46
Expense Ratio, Percent 0.85% [1]
Net Assets $ 925,680,060
Holdings Count | Holding 67
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
925,680,060
Total number of portfolio holdings
67
Portfolio turnover for the reporting period
9%
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.
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR Group Ltd.2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR Group Ltd.2.3
%
Columbia Acorn International® - Class S  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International®
Class Name Class S
Trading Symbol CCIDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International
®
(the Fund) for the period of January 1, 2025 to June 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 S
$
52		0.97
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 52
Expense Ratio, Percent 0.97% [1]
Net Assets $ 925,680,060
Holdings Count | Holding 67
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
925,680,060
Total number of portfolio holdings
67
Portfolio turnover for the reporting period
9%
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.
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR Group Ltd.2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Capcom Co., Ltd.3.2
%
Halma PLC2.8
%
Rightmove PLC2.7
%
Fisher & Paykel Healthcare Corp., Ltd.2.6
%
CTS Eventim AG & Co. KGaA2.6
%
Auto Trader Group PLC2.5
%
Niterra Co., Ltd.
2.4
%
Nemetschek SE2.3
%
Belimo Holding AG, Registered Shares2.3
%
CAR Group Ltd.2.3
%
Columbia Acorn International SelectSM - Class A  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International SelectSM
Class Name Class A
Trading Symbol LAFAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International Select
SM
(the Fund) for the period of January 1, 2025 to June 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
$
62		1.16
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 62
Expense Ratio, Percent 1.16% [1]
Net Assets $ 203,521,015
Holdings Count | Holding 59
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
203,521,015
Total number of portfolio holdings
59
Portfolio turnover for the reporting period
9%
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.
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Columbia Acorn International SelectSM - Institutional Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International SelectSM
Class Name Institutional Class
Trading Symbol ACFFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International Select
SM
(the Fund) for the period of January 1, 2025 to June 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
$
48		0.91
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.91% [1]
Net Assets $ 203,521,015
Holdings Count | Holding 59
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
203,521,015
Total number of portfolio holdings
59
Portfolio turnover for the reporting period
9%
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.
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Columbia Acorn International SelectSM - Institutional 2 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International SelectSM
Class Name Institutional 2 Class
Trading Symbol CRIRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International Select
SM
(the Fund) for the period of January 1, 2025 to June 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
$
41		0.77
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 41
Expense Ratio, Percent 0.77% [1]
Net Assets $ 203,521,015
Holdings Count | Holding 59
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
203,521,015
Total number of portfolio holdings
59
Portfolio turnover for the reporting period
9%
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.
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Columbia Acorn International SelectSM - Institutional 3 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International SelectSM
Class Name Institutional 3 Class
Trading Symbol CSIRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International Select
SM
(the Fund) for the period of January 1, 2025 to June 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
$
38		0.71
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 38
Expense Ratio, Percent 0.71% [1]
Net Assets $ 203,521,015
Holdings Count | Holding 59
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
203,521,015
Total number of portfolio holdings
59
Portfolio turnover for the reporting period
9%
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.
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Columbia Acorn International SelectSM - Class S  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn International SelectSM
Class Name Class S
Trading Symbol ACFEX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn International Select
SM
(the Fund) for the period of January 1, 2025 to June 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 S
$
48		0.91
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.91% [1]
Net Assets $ 203,521,015
Holdings Count | Holding 59
Investment Company, Portfolio Turnover 9.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
203,521,015
Total number of portfolio holdings
59
Portfolio turnover for the reporting period
9%
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.
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Schneider Electric SE3.9
%
Capcom Co., Ltd.3.9
%
3i Group PLC3.2
%
Airbus Group SE2.7
%
Bank of Ireland Group PLC2.7
%
ASML Holding NV2.6
%
Adidas AG2.6
%
Publicis Groupe SA2.5
%
BT Group PLC2.4
%
Nestlé SA, Registered Shares2.3
%
Columbia Thermostat FundSM - Class A  
Shareholder Report [Line Items]  
Fund Name Columbia Thermostat FundSM
Class Name Class A
Trading Symbol CTFAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Thermostat Fund
SM
(the Fund) for the period of January 1, 2025 to June 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
$
25		0.49
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 25
Expense Ratio, Percent 0.49% [1]
Net Assets $ 1,248,605,013
Holdings Count | Holding 12
Investment Company, Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
1,248,605,013
Total number of portfolio holdings
12
Portfolio turnover for the reporting period
60%
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.
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Largest Holdings [Text Block]
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Columbia Thermostat FundSM - Class C  
Shareholder Report [Line Items]  
Fund Name Columbia Thermostat FundSM
Class Name Class C
Trading Symbol CTFDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Thermostat Fund
SM
(the Fund) for the period of January 1, 2025 to June 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
$
64		1.24
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 64
Expense Ratio, Percent 1.24% [1]
Net Assets $ 1,248,605,013
Holdings Count | Holding 12
Investment Company, Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Key Fund
Statistics
Fund net assets
$
1,248,605,013
Total number of portfolio holdings
12
Portfolio turnover for the reporting period
60%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the investment makeup of the Fund repre
se
nted 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.
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Largest Holdings [Text Block]
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Columbia Thermostat FundSM - Institutional Class  
Shareholder Report [Line Items]  
Fund Name Columbia Thermostat FundSM
Class Name Institutional Class
Trading Symbol COTZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Thermostat Fund
SM
(the Fund) for the period of January 1, 2025 to June 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
$
12		0.24
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.24% [1]
Net Assets $ 1,248,605,013
Holdings Count | Holding 12
Investment Company, Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
1,248,605,013
Total number of portfolio holdings
12
Portfolio turnover for the reporting period
60%
Holdings [Text Block]
Graphical Representation of Fund
 
Holdings
The tables below show the investment makeup of the Fund repre
se
nted 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.
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Largest Holdings [Text Block]
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Columbia Thermostat FundSM - Institutional 2 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Thermostat FundSM
Class Name Institutional 2 Class
Trading Symbol CQTRX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Thermostat Fund
SM
(the Fund) for the period of January 1, 2025 to June 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
$
10		0.19
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 10
Expense Ratio, Percent 0.19% [1]
Net Assets $ 1,248,605,013
Holdings Count | Holding 12
Investment Company, Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
1,248,605,013
Total number of portfolio holdings
12
Portfolio turnover for the reporting period
60%
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.
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Largest Holdings [Text Block]
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Columbia Thermostat FundSM - Institutional 3 Class  
Shareholder Report [Line Items]  
Fund Name Columbia Thermostat FundSM
Class Name Institutional 3 Class
Trading Symbol CYYYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Thermostat Fund
SM
(the Fund) for the period of January 1, 2025 to June 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
$
7		0.14
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 7
Expense Ratio, Percent 0.14% [1]
Net Assets $ 1,248,605,013
Holdings Count | Holding 12
Investment Company, Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
1,248,605,013
Total number of portfolio holdings
12
Portfolio turnover for the reporting period
60%
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.
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Largest Holdings [Text Block]
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Columbia Thermostat FundSM - Class S  
Shareholder Report [Line Items]  
Fund Name Columbia Thermostat FundSM
Class Name Class S
Trading Symbol COTDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Thermostat Fund
SM
(the Fund) for the period of January 1, 2025 to June 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 S
$
12		0.24
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 12
Expense Ratio, Percent 0.24% [1]
Net Assets $ 1,248,605,013
Holdings Count | Holding 12
Investment Company, Portfolio Turnover 60.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
1,248,605,013
Total number of portfolio holdings
12
Portfolio turnover for the reporting period
60%
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.
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Asset Categories
Graphical Representation - Allocation 1 Chart
Largest Holdings [Text Block]
Top Holdings
Columbia Total Return Bond Fund, Institutional 3 Class14.9
%
Columbia Corporate Income Fund, Institutional 3 Class11.9
%
Columbia U.S. Treasury Index Fund, Institutional 3 Class11.9
%
Columbia Contrarian Core Fund, Institutional 3 Class10.1
%
Columbia Large Cap Enhanced Core Fund, Institutional 3 Class10.0
%
Columbia Quality Income Fund, Institutional 3 Class9.0
%
Columbia Research Enhanced Core ETF8.1
%
Columbia Large Cap Index Fund, Institutional 3 Class8.0
%
Columbia High Yield Bond Fund, Institutional 3 Class5.9
%
Columbia Diversified Fixed Income Allocation ETF6.0
%
Columbia Acorn European FundSM - Class A  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn European FundSM
Class Name Class A
Trading Symbol CAEAX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn European Fund
SM
(the Fund) for the period of January 1, 2025 to June 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
$
75		1.37
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 75
Expense Ratio, Percent 1.37% [1]
Net Assets $ 41,167,250
Holdings Count | Holding 91
Investment Company, Portfolio Turnover 53.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
41,167,250
Total number of portfolio holdings
91
Portfolio turnover for the reporting period
53%
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 ta
ble
s unless otherwise noted. The Fund's portfolio composition is subject to change.
Top Holdings
Elis SA2.9
%
CTS Eventim AG & Co. KGaA2.3
%
Storebrand ASA2.3
%
Nexans SA2.2
%
Safestore Holdings PLC2.2
%
Quilter PLC2.1
%
LondonMetric Property PLC2.0
%
Buzzi SpA1.8
%
Banco Comercial Portugues SA1.8
%
Chemring Group PLC1.7
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Elis SA2.9
%
CTS Eventim AG & Co. KGaA2.3
%
Storebrand ASA2.3
%
Nexans SA2.2
%
Safestore Holdings PLC2.2
%
Quilter PLC2.1
%
LondonMetric Property PLC2.0
%
Buzzi SpA1.8
%
Banco Comercial Portugues SA1.8
%
Chemring Group PLC1.7
%
Columbia Acorn European FundSM - Institutional Class  
Shareholder Report [Line Items]  
Fund Name Columbia Acorn European FundSM
Class Name Institutional Class
Trading Symbol CAEZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Columbia Acorn European Fund
SM
(the Fund) for the period of January 1, 2025 to June 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
$
62		1.13
%
(a)
(a)
Annualized.
Expenses Paid, Amount $ 62
Expense Ratio, Percent 1.13% [1]
Net Assets $ 41,167,250
Holdings Count | Holding 91
Investment Company, Portfolio Turnover 53.00%
Additional Fund Statistics [Text Block]
Key Fund Statistics
Fund net assets
$
41,167,250
Total number of portfolio holdings
91
Portfolio turnover for the reporting period
53%
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.
Top Holdings
Elis SA2.9
%
CTS Eventim AG & Co. KGaA2.3
%
Storebrand ASA2.3
%
Nexans SA2.2
%
Safestore Holdings PLC2.2
%
Quilter PLC2.1
%
LondonMetric Property PLC2.0
%
Buzzi SpA1.8
%
Banco Comercial Portugues SA1.8
%
Chemring Group PLC1.7
%
Equity Sector Allocation
Graphical Representation - Allocation 1 Chart
Geographic Allocation
Graphical Representation - Allocation 2 Chart
Largest Holdings [Text Block]
Top Holdings
Elis SA2.9
%
CTS Eventim AG & Co. KGaA2.3
%
Storebrand ASA2.3
%
Nexans SA2.2
%
Safestore Holdings PLC2.2
%
Quilter PLC2.1
%
LondonMetric Property PLC2.0
%
Buzzi SpA1.8
%
Banco Comercial Portugues SA1.8
%
Chemring Group PLC1.7
%
[1] Annualized.