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Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Document Type dei_DocumentType 485BPOS
Document Period End Date dei_DocumentPeriodEndDate Dec. 31, 2012
Registrant Name dei_EntityRegistrantName COLUMBIA ACORN TRUST
Central Index Key dei_EntityCentralIndexKey 0000002110
Amendment Flag dei_AmendmentFlag false
Document Creation Date dei_DocumentCreationDate Apr. 30, 2013
Document Effective Date dei_DocumentEffectiveDate May 01, 2013
Prospectus Date rr_ProspectusDate May 01, 2013
(Columbia Acorn Fund)
  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds. More information about these and other discounts is available from your financial advisor, in the Choosing a Share Class section beginning on page 20 of this prospectus and in Appendix S to the Statement of Additional Information under Sales Charge Waivers beginning on page S-1. The Fund no longer accepts investments from new or existing investors in Class B shares. Class I shares are generally available only to other Columbia Funds.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 16% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 16.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

  • you invest $10,000 in Class A, Class B, Class C, Class I, Class R4, Class R5, Class Y or Class Z shares of the Fund for the periods indicated,

  • your investment has a 5% return each year, and

  • the Fund's total annual operating expenses remain the same as shown in the table above.
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock

Remember this is an example only. Your actual costs may be higher or lower.

Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $5 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $5 billion. Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Fund invests the majority of its assets in U.S. companies, but also may invest up to 33% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil).

The Investment Manager typically seeks companies with:

  • A strong business franchise that offers growth potential.

  • Products and services that give the company a competitive advantage.

  • A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

  • Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

  • Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

  • Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller companies may not be widely followed by the investment community, which can lower the demand for their stocks.

  • Sector Risk – At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

  • Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.

    Operational and Settlement Risks of Foreign Securities. The Fund's foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies ("foreign sub-custodians"), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

    Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer's securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

  • Emerging Market Securities Risk – Securities issued by foreign governments or companies in emerging market countries, like Russia and those in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.

    Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.

    Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not be traded internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country's economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

    Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in Russia.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart below and table on the following page show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The inception date for the Fund's Class I shares is September 27, 2010; and the inception date for the Fund's Class R4, Class R5 and Class Y shares is November 8, 2012. The returns shown for these share classes include the returns of the Fund's Class Z shares for periods prior to their inception dates. Except for differences in expenses, these classes of shares have annual returns substantially similar to those of Class Z shares, because all classes of the Fund's shares invest in the same portfolio of securities.

The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 800.345.6611
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.columbiamanagement.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year

[10]
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock 

Best and Worst Quarterly Returns During this Period

Best:     2nd quarter 2009:    20.90%

Worst:    4th quarter 2008:   -25.11%
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Return as of December 31, 2012

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Class Z shares and will vary for other share classes.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

The table compares the Fund's returns for each period with those of the Russell 2500 Index, the Fund's primary benchmark, the Standard & Poor's (S&P) 500® Index and the Russell 2000 Index. The Russell 2500 Index measures the performance of the 2,500 smallest companies in the Russell 3000 Index, which represents approximately 17% of the total market capitalization of the Russell 3000 Index. The S&P 500® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. Although the Fund typically invests in small and mid-sized companies, the comparison to the S&P 500® Index is presented to show performance against a widely recognized market index. The Russell 2000 Index measures the performance of the 2,000 smallest companies in the Russell 3000 Index, which represents approximately 10% of the total market capitalization of the Russell 3000 Index. The Russell 2000 Index shows how the Fund's performance compares to a widely recognized broad based index of companies with somewhat lower capitalization than the Fund's primary benchmark.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown only for Class Z shares and will vary for other share classes.
(Columbia Acorn Fund) | Russell 2500 Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 17.88%
5 Years rr_AverageAnnualReturnYear05 4.34%
10 Years rr_AverageAnnualReturnYear10 10.49%
(Columbia Acorn Fund) | S&P 500® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.00%
5 Years rr_AverageAnnualReturnYear05 1.66%
10 Years rr_AverageAnnualReturnYear10 7.10%
(Columbia Acorn Fund) | Russell 2000 Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.35%
5 Years rr_AverageAnnualReturnYear05 3.56%
10 Years rr_AverageAnnualReturnYear10 9.72%
(Columbia Acorn Fund) | Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Management fees rr_ManagementFeesOverAssets 0.64%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.21% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.10%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 681
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 905
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,146
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,838
1 Year rr_AverageAnnualReturnYear01 10.87%
5 Years rr_AverageAnnualReturnYear05 2.47%
10 Years rr_AverageAnnualReturnYear10 10.59%
(Columbia Acorn Fund) | Class B Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 5.00% [2]
Management fees rr_ManagementFeesOverAssets 0.64%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other expenses rr_OtherExpensesOverAssets 0.33% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.72%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 675
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 842
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,133
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,866
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 175
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 542
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 933
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 1,866
1 Year rr_AverageAnnualReturnYear01 11.98%
5 Years rr_AverageAnnualReturnYear05 2.75%
10 Years rr_AverageAnnualReturnYear10 10.57%
(Columbia Acorn Fund) | Class C Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [3]
Management fees rr_ManagementFeesOverAssets 0.64%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.17% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.81%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 284
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 569
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 980
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,127
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 184
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 569
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 980
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,127
1 Year rr_AverageAnnualReturnYear01 15.77%
5 Years rr_AverageAnnualReturnYear05 2.89%
10 Years rr_AverageAnnualReturnYear10 10.41%
(Columbia Acorn Fund) | Class I Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.64%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.08% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.72%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 74
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 230
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 401
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 894
1 Year rr_AverageAnnualReturnYear01 18.02%
5 Years rr_AverageAnnualReturnYear05 4.03%
10 Years rr_AverageAnnualReturnYear10 11.64%
(Columbia Acorn Fund) | Class R4 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.64%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.28% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.92%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 94
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 293
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 509
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,131
1 Year rr_AverageAnnualReturnYear01 17.93%
5 Years rr_AverageAnnualReturnYear05 4.00%
10 Years rr_AverageAnnualReturnYear10 11.62%
(Columbia Acorn Fund) | Class R5 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.64%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.13% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.77%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 79
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 246
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 428
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 954
1 Year rr_AverageAnnualReturnYear01 17.95%
5 Years rr_AverageAnnualReturnYear05 4.00%
10 Years rr_AverageAnnualReturnYear10 11.62%
(Columbia Acorn Fund) | Class Y Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.64%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.08% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.72%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 74
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 230
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 401
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 894
1 Year rr_AverageAnnualReturnYear01 17.96%
5 Years rr_AverageAnnualReturnYear05 4.00%
10 Years rr_AverageAnnualReturnYear10 11.62%
(Columbia Acorn Fund) | Class Z Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.64%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.18% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.82%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 84
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 262
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 455
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,014
Annual Return 2003 rr_AnnualReturn2003 45.68%
Annual Return 2004 rr_AnnualReturn2004 21.51%
Annual Return 2005 rr_AnnualReturn2005 13.11%
Annual Return 2006 rr_AnnualReturn2006 14.45%
Annual Return 2007 rr_AnnualReturn2007 7.69%
Annual Return 2008 rr_AnnualReturn2008 (38.55%)
Annual Return 2009 rr_AnnualReturn2009 39.65%
Annual Return 2010 rr_AnnualReturn2010 26.00%
Annual Return 2011 rr_AnnualReturn2011 (4.61%)
Annual Return 2012 rr_AnnualReturn2012 17.93%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel 2nd quarter 2009:
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 20.90%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel 4th quarter 2008:
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (25.11%)
1 Year rr_AverageAnnualReturnYear01 17.93%
5 Years rr_AverageAnnualReturnYear05 4.00%
10 Years rr_AverageAnnualReturnYear10 11.62%
(Columbia Acorn Fund) | Class Z Shares | returns after taxes on distributions
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.81%
5 Years rr_AverageAnnualReturnYear05 3.48%
10 Years rr_AverageAnnualReturnYear10 10.92%
(Columbia Acorn Fund) | Class Z Shares | returns after taxes on distributions and sale of Fund shares
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 13.07%
5 Years rr_AverageAnnualReturnYear05 3.37%
10 Years rr_AverageAnnualReturnYear10 10.30%
(Columbia Acorn European Fund)
  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds. More information about these and other discounts is available from your financial advisor, in the Choosing a Share Class section beginning on page 20 of this prospectus and in Appendix S to the Statement of Additional Information under Sales Charge Waivers beginning on page S-1. Class I shares are generally available only to other Columbia Funds.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination 2014-04-30
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 37% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 37.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

  • you invest $10,000 in Class A, Class C, Class I, Class R5 or Class Z shares of the Fund for the periods indicated,

  • your investment has a 5% return each year, and

  • the Fund's total annual operating expenses remain the same as shown in the table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire on April 30, 2014, they are only reflected in the 1 year example and the first year of the 3, 5 and 10 year examples.

Based on the assumptions listed above, your costs would be:
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock

Remember this is an example only. Your actual costs may be higher or lower.

Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 80% of its net assets (plus any borrowing for investment purposes) in European companies. Under normal circumstances, the Fund invests at least 70% of its total assets in companies in Western European countries (for example, the United Kingdom, Germany, France and Italy), but also may invest up to 30% of its total assets in companies in emerging Central and Eastern European countries (for example, Poland, the Czech Republic, Turkey and Cyprus), including up to 10% of its total assets in companies in Russia and the Ukraine. For purposes of the Fund's policies, the Fund may invest in a company if (i) it is domiciled in, or the principal trading market for its securities is in, a European country, (ii) it derives 50% or more of its economic value from goods produced, sales made or services performed or has at least 50% of its assets in a European country or (iii) it is a holding company that predominantly holds shares in such companies. The Fund may invest in a variety of countries, industries and sectors and does not attempt to invest a specific percentage of its assets in any given country, industry or sector.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $5 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $5 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Fund takes advantage of the Investment Manager's research and stock-picking capabilities to initially invest in a limited number of companies (generally under 100), offering the potential to provide above-average growth over time.

The Investment Manager typically seeks companies with:

  • A strong business franchise that offers growth potential.

  • Products and services that give the company a competitive advantage.

  • A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

  • Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

  • Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

  • Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller companies may not be widely followed by the investment community, which can lower the demand for their stocks.

  • Sector Risk – At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

  • Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.

    Operational and Settlement Risks of Foreign Securities. The Fund's foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies ("foreign sub-custodians"), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

    Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer's securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

  • Emerging Market Securities Risk – Securities issued by foreign governments or companies in emerging market countries, like Russia and those in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.

    Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.

    Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not be traded internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country's economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

    Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in Russia.

  • Currency Risk – Securities denominated in non-U.S. dollar currencies are subject to the risk that, for example, if the value of a foreign currency were to decline against the U.S. dollar, such decline would reduce the U.S. dollar value of any securities held by the Fund denominated in that currency.

  • Special Situations Risk – Securities of companies that are involved in an initial public offering or a major corporate event, such as a business consolidation or restructuring, may present special risk because of the high degree of uncertainty that can be associated with such events. Securities issued in initial public offerings often are issued by companies that are in the early stages of development, have a history of little or no revenues and may operate at a loss following the offering. It is possible that there will be no active trading market for the securities after the offering, and that the market price of the securities may be subject to significant and unpredictable fluctuations. Investing in special situations may have a magnified effect on the performance of funds with small amounts of assets.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart below and table on the following page show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The inception date for the Fund's Class R5 shares is November 8, 2012. The returns shown for this share class includes the returns of the Fund's Class Z shares for periods prior to its inception date. Except for differences in expenses, this class of shares has annual returns substantially similar to those of Class Z shares, because all classes of the Fund's shares invest in the same portfolio of securities.

The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 800.345.6611
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.columbiamanagement.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year

[11]
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock 

Best and Worst Quarterly Returns During this Period

Best:     1st quarter 2012:     17.69%

Worst:    2nd quarter 2012:    -5.16%
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Return as of December 31, 2012

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Class Z shares and will vary for other share classes.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

The table compares the Fund's returns, for each period, with those of the Standard & Poor's (S&P) Europe Between $500 Million and $5 Billion® Index, the Fund's primary benchmark, and the HSBC Smaller European Companies (inc UK) Index. The S&P Europe Between $500 Million and $5 Billion® Index is representative of the institutionally investable capital of 17 European countries (as of December 31, 2012), as determined by S&P, with market caps ranging between $500 million to $5 billion. The HSBC Smaller European Companies (inc UK) Index is a quarterly rebalanced, weighted combination of two indexes: the HSBC Smaller Europe (ex UK) Index and the HSBC Smaller UK Index. The performance of the HSBC Smaller European Companies (inc UK) Index is provided to show how the Fund's performance compares to a widely recognized index of small-capitalization equity performance in European markets.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown only for Class Z shares and will vary for other share classes.
(Columbia Acorn European Fund) | S&P Europe Between $500 Million and $5 Billion® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 28.24%
Life of Fund rr_AverageAnnualReturnSinceInception 13.57%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn European Fund) | HSBC Smaller European Companies Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 25.89%
Life of Fund rr_AverageAnnualReturnSinceInception 9.96%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn European Fund) | Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Management fees rr_ManagementFeesOverAssets 1.19%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 8.60% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 10.04%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (8.29%) [7]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.75%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 743
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 2,599
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 4,274
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 7,775
1 Year rr_AverageAnnualReturnYear01 18.19%
Life of Fund rr_AverageAnnualReturnSinceInception 8.89%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn European Fund) | Class C Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [3]
Management fees rr_ManagementFeesOverAssets 1.19%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 8.78% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 10.97%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (8.47%) [7]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 2.50%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 353
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 2,370
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 4,241
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 8,025
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 253
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 2,370
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 4,241
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 8,025
1 Year rr_AverageAnnualReturnYear01 23.46%
Life of Fund rr_AverageAnnualReturnSinceInception 12.89%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn European Fund) | Class I Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 1.19%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 8.46% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 9.65%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (8.19%) [7]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.46%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 149
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 2,055
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 3,788
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 7,464
1 Year rr_AverageAnnualReturnYear01 25.71%
Life of Fund rr_AverageAnnualReturnSinceInception 14.00%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn European Fund) | Class R5 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 1.19%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 8.51% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 9.70%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (8.19%) [7]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.51%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 154
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 2,068
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 3,807
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 7,487
1 Year rr_AverageAnnualReturnYear01 25.46%
Life of Fund rr_AverageAnnualReturnSinceInception 13.70%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn European Fund) | Class Z Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 1.19%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 8.50% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 9.69%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (8.19%) [7]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.50%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 153
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 2,065
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 3,803
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 7,482
Annual Return 2012 rr_AnnualReturn2012 25.66%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel 1st quarter 2012:
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 17.69%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel 2nd quarter 2012:
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (5.16%)
1 Year rr_AverageAnnualReturnYear01 25.66%
Life of Fund rr_AverageAnnualReturnSinceInception 14.00%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn European Fund) | Class Z Shares | returns after taxes on distributions
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 25.66%
Life of Fund rr_AverageAnnualReturnSinceInception 13.81%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn European Fund) | Class Z Shares | returns after taxes on distributions and sale of Fund shares
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 17.04%
Life of Fund rr_AverageAnnualReturnSinceInception 11.94%
Inception Date rr_AverageAnnualReturnInceptionDate Aug. 19, 2011
(Columbia Acorn Emerging Markets Fund)
  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds. More information about these and other discounts is available from your financial advisor, in the Choosing a Share Class section beginning on page 22 of this prospectus and in Appendix S to the Statement of Additional Information under Sales Charge Waivers beginning on page S-1. Class I shares are generally available only to other Columbia Funds.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination 2014-04-30
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 30% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 30.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

  • you invest $10,000 in Class A, Class C, Class I, Class R4, Class R5, Class Y or Class Z shares of the Fund for the periods indicated,

  • your investment has a 5% return each year, and

  • the Fund's total annual operating expenses remain the same as shown in the table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire on April 30, 2014, they are only reflected in the 1 year example and the first year of the 3, 5 and 10 year examples.

Based on the assumptions listed above, your costs would be:
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock

Remember this is an example only. Your actual costs may be higher or lower.

Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 80% of its net assets (plus any borrowing for investment purposes) in companies located in emerging market countries, including frontier market countries. Emerging market countries are those countries whose economies are developing or emerging from underdevelopment (for example, China, India, Poland and Turkey). Frontier market countries generally have smaller economies and even less developed capital markets than traditional emerging market countries (for example, Vietnam, Colombia, Nigeria and Kazakhstan). For purposes of the Fund's policies, the Fund may invest in a company if (i) it is domiciled in, or the principal trading market for its securities is in, an emerging market country, (ii) it derives 50% or more of its economic value from goods produced, sales made or services performed or has at least 50% of its assets in an emerging market country or countries or (iii) it is a holding company that predominantly holds shares in such companies. The Fund may invest in a variety of countries, industries and sectors and does not attempt to invest a specific percentage of its assets in any given country, industry or sector.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $5 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $5 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Fund takes advantage of the Investment Manager's research and stock-picking capabilities to initially invest in a limited number of companies (generally under 100), offering the potential to provide above-average growth over time.

Generally, the Investment Manager will determine which countries are emerging market countries by reference to the countries included in the S&P Emerging Markets Broad Market Index (BMI), and will determine which countries are frontier market countries by reference to the countries included in the S&P Frontier BMI. In addition, the Fund may invest in certain developing market countries that are not included in either the S&P Emerging Markets BMI or the S&P Frontier BMI (for example, Serbia and Senegal), but which are included on another independent third-party listing of emerging market and/or frontier market countries. The Investment Manager will make all determinations as to whether a company is an emerging market company at the time of investment. The countries that comprise emerging market countries, including frontier market countries, may change from time to time.

The Investment Manager typically seeks companies with:

  • A strong business franchise that offers growth potential.

  • Products and services that give the company a competitive advantage.

  • A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

  • Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

  • Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

  • Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.

    Operational and Settlement Risks of Foreign Securities. The Fund's foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies ("foreign sub-custodians"), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

    Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer's securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

  • Emerging Market Securities Risk – Securities issued by foreign governments or companies in emerging market countries, like Russia and those in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.

    Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.

    Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not be traded internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country's economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

    Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in Russia.

  • Frontier Market Risk — Frontier market countries generally have smaller economies and even less developed capital markets than traditional emerging market countries and, as a result, the risks of investing in emerging market countries are magnified in frontier market countries. The magnification of risks are the result of: potential for extreme price volatility and illiquidity in frontier market countries; government ownership or control of parts of private sector and of certain companies; trade barriers, exchange controls, managed adjustments in relative currency values and other protectionist measures imposed or negotiated by the countries with which frontier market countries trade; and the relatively new and unsettled securities laws in many frontier market countries.

  • Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller companies may not be widely followed by the investment community, which can lower the demand for their stocks.

  • Currency Risk – Securities denominated in non-U.S. dollar currencies are subject to the risk that, for example, if the value of a foreign currency were to decline against the U.S. dollar, such decline would reduce the U.S. dollar value of any securities held by the Fund denominated in that currency.

  • Sector Risk – At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

  • Special Situations Risk – Securities of companies that are involved in an initial public offering or a major corporate event, such as a business consolidation or restructuring, may present special risk because of the high degree of uncertainty that can be associated with such events. Securities issued in initial public offerings often are issued by companies that are in the early stages of development, have a history of little or no revenues and may operate at a loss following the offering. It is possible that there will be no active trading market for the securities after the offering, and that the market price of the securities may be subject to significant and unpredictable fluctuations. Investing in special situations may have a magnified effect on the performance of funds with small amounts of assets.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart below and table on the following page show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The inception date for the Fund's Class R4 and Class R5 shares is November 8, 2012. The returns shown for these share classes include the returns of the Fund's Class Z shares for periods prior to their inception dates. The Fund's Class Y shares had not commenced operations as of the date of this prospectus and therefore have no performance information to report. Except for differences in expenses, these classes of shares have annual returns substantially similar to those of Class Z shares, because all classes of the Fund's shares invest in the same portfolio of securities.

The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 800.345.6611
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.columbiamanagement.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year

[12]
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock 

Best and Worst Quarterly Returns During this Period

Best:    1st quarter 2012:    17.69%

Worst:   2nd quarter 2012:    -5.16%
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Return as of December 31, 2012

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Class Z shares and will vary for other share classes.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

The table compares the Fund's returns, for each period, with those of the Standard & Poor's (S&P) Emerging Markets Between $500 Million and $5 Billion® Index, the Fund's primary benchmark, and the MSCI Emerging Markets Small Cap Index (Net). The S&P Emerging Markets Between $500 Million and $5 Billion® Index is representative of the institutionally investable capital of 21 emerging market countries (as of December 31, 2012), as determined by S&P, with market caps ranging between $500 million to $5 billion. The MSCI Emerging Markets Small Cap Index (Net) is a widely recognized international benchmark, and a free float-adjusted market capitalization index that is designed to measure small-cap emerging market equity performance is 21 emerging market countries (as of December 31, 2012), as determined by MSCI. The performance of the MSCI Emerging Markets Small Cap Index (Net) is provided to show how the Fund's performance compares to a widely recognized index of small-capitalization equity performance in less developed markets.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown only for Class Z shares and will vary for other share classes.
(Columbia Acorn Emerging Markets Fund) | MSCI Emerging Markets Small Cap Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 22.22%
Life of Fund rr_AverageAnnualReturnSinceInception 1.36%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | S&P Emerging Markets Between $500 Million and $5 Billion® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 25.71%
Life of Fund rr_AverageAnnualReturnSinceInception 6.34%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Management fees rr_ManagementFeesOverAssets 1.25%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 4.07% [5]
Total annual Fund operating expenses rr_ExpensesOverAssets 5.57%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (3.72%) [8]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.85%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 752
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,829
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,894
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 5,502
1 Year rr_AverageAnnualReturnYear01 23.40%
Life of Fund rr_AverageAnnualReturnSinceInception 10.19%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | Class C Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [3]
Management fees rr_ManagementFeesOverAssets 1.25%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 4.12% [5]
Total annual Fund operating expenses rr_ExpensesOverAssets 6.37%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (3.77%) [8]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 2.60%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 363
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,550
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,802
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 5,784
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 263
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 1,550
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 2,802
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 5,784
1 Year rr_AverageAnnualReturnYear01 28.98%
Life of Fund rr_AverageAnnualReturnSinceInception 14.31%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | Class I Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 1.25%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 3.93% [5]
Total annual Fund operating expenses rr_ExpensesOverAssets 5.18%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (3.64%) [8]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.54%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 157
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,227
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,293
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 4,941
1 Year rr_AverageAnnualReturnYear01 31.39%
Life of Fund rr_AverageAnnualReturnSinceInception 15.66%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | Class R4 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 1.25%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 4.13% [5]
Total annual Fund operating expenses rr_ExpensesOverAssets 5.38%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (3.78%) [8]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.60%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 163
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,271
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,371
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 5,085
1 Year rr_AverageAnnualReturnYear01 30.97%
Life of Fund rr_AverageAnnualReturnSinceInception 15.12%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | Class R5 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 1.25%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 3.98% [5]
Total annual Fund operating expenses rr_ExpensesOverAssets 5.23%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (3.64%) [8]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.59%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 162
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,241
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,315
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 4,979
1 Year rr_AverageAnnualReturnYear01 31.05%
Life of Fund rr_AverageAnnualReturnSinceInception 15.17%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | Class Y Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 1.25%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 3.93% [5]
Total annual Fund operating expenses rr_ExpensesOverAssets 5.18%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (3.64%) [8]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.54%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 157
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,227
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,293
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 4,941
(Columbia Acorn Emerging Markets Fund) | Class Z Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 1.25%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 3.99% [5]
Total annual Fund operating expenses rr_ExpensesOverAssets 5.24%
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (3.64%) [8]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.60%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 163
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,244
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 2,320
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 4,987
Annual Return 2012 rr_AnnualReturn2012 31.35%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel 1st quarter 2012:
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 18.00%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel 2nd quarter 2012:
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (6.90%)
1 Year rr_AverageAnnualReturnYear01 31.35%
Life of Fund rr_AverageAnnualReturnSinceInception 15.55%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | Class Z Shares | returns after taxes on distributions
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 31.25%
Life of Fund rr_AverageAnnualReturnSinceInception 15.49%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn Emerging Markets Fund) | Class Z Shares | returns after taxes on distributions and sale of Fund shares
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 20.71%
Life of Fund rr_AverageAnnualReturnSinceInception 13.33%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 30, 2014
(Columbia Acorn International)
  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds. More information about these and other discounts is available from your financial advisor, in the Choosing a Share Class section beginning on page 21 of this prospectus and in Appendix S to the Statement of Additional Information under Sales Charge Waivers beginning on page S-1. The Fund no longer accepts investments from new or existing investors in Class B shares. Class I shares are generally available only to other Columbia Funds.

Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 33% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 33.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

  • you invest $10,000 in Class A, Class B, Class C, Class I, Class R, Class R4, Class R5, Class Y or Class Z shares of the Fund for the periods indicated,

  • your investment has a 5% return each year, and

  • the Fund's total annual operating expenses remain the same as shown in the table above.

Based on the assumptions listed above, your costs would be:
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock

Remember this is an example only. Your actual costs may be higher or lower.

Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 75% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil).

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $5 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $5 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Investment Manager typically seeks companies with:

  • A strong business franchise that offers growth potential.

  • Products and services that give the company a competitive advantage.

  • A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

  • Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

  • Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

  • Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller companies may not be widely followed by the investment community, which can lower the demand for their stocks.

  • Sector Risk – At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

  • Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.

    Operational and Settlement Risks of Foreign Securities. The Fund's foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies ("foreign sub-custodians"), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

    Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer's securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

  • Emerging Market Securities Risk – Securities issued by foreign governments or companies in emerging market countries, like Russia and those in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.

    Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.

    Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not be traded internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country's economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

    Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in Russia.

  • Currency Risk – Securities denominated in non-U.S. dollar currencies are subject to the risk that, for example, if the value of a foreign currency were to decline against the U.S. dollar, such decline would reduce the U.S. dollar value of any securities held by the Fund denominated in that currency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart below and table on the following page show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The inception date for the Fund's Class I shares is September 27, 2010; the inception date for the Fund's Class R and R5 shares is August 2, 2011 and the inception date for the Fund's Class R4 and Class Y shares is November 8, 2012. The returns shown for these share classes include the returns of the Fund's Class Z shares for periods prior to their inception dates. Except for differences in expenses, these classes of shares have annual returns substantially similar to those of Class Z shares, because all classes of the Fund's shares invest in the same portfolio of securities.

The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 800.345.6611
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.columbiamanagement.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year

 [13]
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.

Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock 

Best and Worst Quarterly Returns During this Period

Best:     2nd quarter 2009:       33.30%

Worst:    3rd quarter 2008:      -23.68%
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Return as of December 31, 2012

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Class Z shares and will vary for other share classes.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

The table compares the Fund's returns, for each period, with those of the Standard & Poor's (S&P) Global Ex-U.S. Between $500 Million and $5 Billion® Index, the Fund's primary benchmark, the S&P Global Ex-U.S. SmallCap® Index and the MSCI Europe, Australasia and Far East (EAFE) Index (Net). The S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index is a subset of the broad market selected by the index sponsor that represents the mid- and small-cap developed and emerging markets, excluding the United States. The S&P Global Ex-U.S. SmallCap® Index is an unmanaged index consisting of the bottom 20% of institutionally investable capital of developed and emerging countries, excluding the United States. The performance of the S&P Global Ex-U.S. Small Cap® Index is provided to show how the Fund's performance compares to foreign market performance with a similar geographic distribution and wider market cap range than the Fund's primary benchmark. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown only for Class Z shares and will vary for other share classes.
(Columbia Acorn International) | S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 19.17%
5 Years rr_AverageAnnualReturnYear05 (0.04%)
10 Years rr_AverageAnnualReturnYear10 13.92%
(Columbia Acorn International) | S&P Global Ex-U.S. SmallCap® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 20.35%
5 Years rr_AverageAnnualReturnYear05 (0.78%)
10 Years rr_AverageAnnualReturnYear10 13.20%
(Columbia Acorn International) | MSCI EAFE Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 17.32%
5 Years rr_AverageAnnualReturnYear05 (3.69%)
10 Years rr_AverageAnnualReturnYear10 8.21%
(Columbia Acorn International) | Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.30% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.31%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 701
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 966
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,252
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,063
1 Year rr_AverageAnnualReturnYear01 14.25%
5 Years rr_AverageAnnualReturnYear05 (0.62%)
10 Years rr_AverageAnnualReturnYear10 13.34%
(Columbia Acorn International) | Class B Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 5.00% [2]
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other expenses rr_OtherExpensesOverAssets 0.53% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 2.04%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 707
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 940
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,298
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,181
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 207
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 640
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,098
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,181
1 Year rr_AverageAnnualReturnYear01 15.33%
5 Years rr_AverageAnnualReturnYear05 (0.47%)
10 Years rr_AverageAnnualReturnYear10 13.26%
(Columbia Acorn International) | Class C Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none [3]
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.29% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 2.05%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 308
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 643
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,103
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,379
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 208
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 643
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,103
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,379
1 Year rr_AverageAnnualReturnYear01 19.31%
5 Years rr_AverageAnnualReturnYear05 (0.21%)
10 Years rr_AverageAnnualReturnYear10 13.16%
(Columbia Acorn International) | Class I Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.11% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.87%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 89
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 278
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 482
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,073
1 Year rr_AverageAnnualReturnYear01 21.69%
5 Years rr_AverageAnnualReturnYear05 0.96%
10 Years rr_AverageAnnualReturnYear10 14.46%
(Columbia Acorn International) | Class R Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other expenses rr_OtherExpensesOverAssets 0.36% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.62%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 165
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 511
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 881
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,922
1 Year rr_AverageAnnualReturnYear01 20.83%
5 Years rr_AverageAnnualReturnYear05 0.30%
10 Years rr_AverageAnnualReturnYear10 13.72%
(Columbia Acorn International) | Class R4 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.31% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.07%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 109
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 340
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 590
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,306
1 Year rr_AverageAnnualReturnYear01 21.57%
5 Years rr_AverageAnnualReturnYear05 0.93%
10 Years rr_AverageAnnualReturnYear10 14.44%
(Columbia Acorn International) | Class R5 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.15% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.91%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 93
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 290
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 504
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,120
1 Year rr_AverageAnnualReturnYear01 21.61%
5 Years rr_AverageAnnualReturnYear05 0.92%
10 Years rr_AverageAnnualReturnYear10 14.43%
(Columbia Acorn International) | Class Y Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.11% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.87%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 89
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 278
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 482
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,073
1 Year rr_AverageAnnualReturnYear01 21.58%
5 Years rr_AverageAnnualReturnYear05 0.93%
10 Years rr_AverageAnnualReturnYear10 14.44%
(Columbia Acorn International) | Class Z Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.76%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.19% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.95%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 97
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 303
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 525
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,166
Annual Return 2003 rr_AnnualReturn2003 47.80%
Annual Return 2004 rr_AnnualReturn2004 29.47%
Annual Return 2005 rr_AnnualReturn2005 21.81%
Annual Return 2006 rr_AnnualReturn2006 34.53%
Annual Return 2007 rr_AnnualReturn2007 17.28%
Annual Return 2008 rr_AnnualReturn2008 (45.89%)
Annual Return 2009 rr_AnnualReturn2009 50.97%
Annual Return 2010 rr_AnnualReturn2010 22.70%
Annual Return 2011 rr_AnnualReturn2011 (14.06%)
Annual Return 2012 rr_AnnualReturn2012 21.60%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel 2nd quarter 2009:
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 33.30%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel 3rd quarter 2008:
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (23.68%)
1 Year rr_AverageAnnualReturnYear01 21.60%
5 Years rr_AverageAnnualReturnYear05 0.93%
10 Years rr_AverageAnnualReturnYear10 14.44%
(Columbia Acorn International) | Class Z Shares | returns after taxes on distributions
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 21.33%
5 Years rr_AverageAnnualReturnYear05 0.57%
10 Years rr_AverageAnnualReturnYear10 13.86%
(Columbia Acorn International) | Class Z Shares | returns after taxes on distributions and sale of Fund shares
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 14.64%
5 Years rr_AverageAnnualReturnYear05 0.73%
10 Years rr_AverageAnnualReturnYear10 13.03%
(Columbia Acorn International Select)
  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds. More information about these and other discounts is available from your financial advisor, in the Choosing a Share Class section beginning on page 22 of this prospectus and in Appendix S to the Statement of Additional Information under Sales Charge Waivers beginning on page S-1. The Fund no longer accepts investments from new or existing investors in Class B shares. Class I shares are generally available only to other Columbia Funds.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 63% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 63.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

  • you invest $10,000 in Class A, Class B, Class C, Class I, Class R4, Class R5, Class Y or Class Z shares of the Fund for the periods indicated,

  • your investment has a 5% return each year, and

  • the Fund's total annual operating expenses remain the same as shown in the table above.

Based on the assumptions listed above, your costs would be:
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock

Remember this is an example only. Your actual costs may be higher or lower.

Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 65% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom). The Fund also may invest up to 35% of its total assets in companies in emerging markets (for example, China, India and Brazil). The Fund generally invests in at least three countries other than the United States but may invest up to 25% of its total assets in securities of U.S. issuers.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $25 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $25 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $25 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $25 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $25 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies.

The Fund takes advantage of the Investment Manager's research and stock-picking capabilities to invest in a limited number of foreign companies (generally between 40-60), offering the potential to provide above-average growth over time.

The Investment Manager typically seeks companies with:

  • A strong business franchise that offers growth potential.

  • Products and services that give the company a competitive advantage.

  • A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

  • Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

  • Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

  • Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller companies may not be widely followed by the investment community, which can lower the demand for their stocks.

  • Sector Risk – At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

  • Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.

    Operational and Settlement Risks of Foreign Securities. The Fund's foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies ("foreign sub-custodians"), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

    Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer's securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

  • Emerging Market Securities Risk – Securities issued by foreign governments or companies in emerging market countries, like Russia and those in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.

    Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.

    Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not be traded internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country's economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

    Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in Russia.

  • Real Estate Investment Trusts Risk – Investment in real estate investment trusts (REITs) and in securities of other companies (wherever organized) principally engaged in the real estate industry subjects the Fund to, among other risks, risks similar to those of direct investments in real estate and the real estate industry in general, including risks related to general and local economic conditions, possible lack of availability of financing and changes in interest rates or property values. REITs are entities that either own properties or make construction or mortgage loans, and also may include operating or finance companies. The value of REIT shares is affected by, among other factors, changes in the value of the underlying properties owned by the REIT, by changes in the prospect for earnings and/or cash flow growth of the REIT itself, defaults by borrowers or tenants, market saturation, decreases in market rates for rents, and other economic, political, or regulatory matters affecting the real estate industry, including REITs. REITs and similar non-U.S. entities depend upon specialized management skills, may have limited financial resources, may have less trading volume in their securities, and may be subject to more abrupt or erratic price movements than the overall securities markets. REITs are also subject to the risk of failing to qualify for tax-free pass-through of income. Some REITs (especially mortgage REITs) are affected by risks similar to those associated with investments in debt securities including changes in interest rates and the quality of credit extended.

    Because the Fund may concentrate its investments in REITs that invest in a particular country or region, the Fund may have a greater risk of loss in the event of a drop in real estate values in that country or region.

  • Currency Risk – Securities denominated in non-U.S. dollar currencies are subject to the risk that, for example, if the value of a foreign currency were to decline against the U.S. dollar, such decline would reduce the U.S. dollar value of any securities held by the Fund denominated in that currency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart below and table on the following page show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The inception date for the Fund's Class I shares is September 27, 2010 and the inception date for the Fund's Class R4, Class R5 and Class Y shares is November 8, 2012. The returns shown for these share classes include the returns of the Fund's Class Z shares for periods prior to their inception dates. Except for differences in expenses, these share classes have annual returns substantially similar to those of Class Z shares, because all classes of the Fund's shares invest in the same portfolio of securities.

The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 800.345.6611
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.columbiamanagement.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year

[14]
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock 

Best and Worst Quarterly Returns During this Period

Best:    2nd quarter 2009:       23.44%

Worst:   3rd quarter 2008:      -24.76%
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Return as of December 31, 2012

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Class Z shares and will vary for other share classes.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

The table compares the Fund's returns, for each period, with those of the Standard & Poor's (S&P) Developed Ex-U.S. Between $2 Billion and $10 Billion® Index, the Fund's primary benchmark, and the MSCI Europe, Australasia and Far East (EAFE) Index (Net). The S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index is a subset of the broad market selected by the index sponsor that represents the mid-cap developed market excluding the United States. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown only for Class Z shares and will vary for other share classes.
(Columbia Acorn International Select) | S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.78%
5 Years rr_AverageAnnualReturnYear05 (1.86%)
10 Years rr_AverageAnnualReturnYear10 11.17%
(Columbia Acorn International Select) | MSCI EAFE Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 17.32%
5 Years rr_AverageAnnualReturnYear05 (3.69%)
10 Years rr_AverageAnnualReturnYear10 8.21%
(Columbia Acorn International Select) | Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Management fees rr_ManagementFeesOverAssets 0.94%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.32% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.51%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 720
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 1,025
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,351
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,273
1 Year rr_AverageAnnualReturnYear01 15.03%
5 Years rr_AverageAnnualReturnYear05 (1.04%)
10 Years rr_AverageAnnualReturnYear10 12.22%
(Columbia Acorn International Select) | Class B Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 5.00% [2]
Management fees rr_ManagementFeesOverAssets 0.94%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other expenses rr_OtherExpensesOverAssets 0.47% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 2.16%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 719
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 976
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,359
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,328
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 219
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 676
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,159
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,328
1 Year rr_AverageAnnualReturnYear01 16.29%
5 Years rr_AverageAnnualReturnYear05 (0.82%)
10 Years rr_AverageAnnualReturnYear10 12.15%
(Columbia Acorn International Select) | Class C Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [3]
Management fees rr_ManagementFeesOverAssets 0.94%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.35% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 2.29%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 332
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 715
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,225
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,626
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 232
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 715
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,225
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,626
1 Year rr_AverageAnnualReturnYear01 20.10%
5 Years rr_AverageAnnualReturnYear05 (0.65%)
10 Years rr_AverageAnnualReturnYear10 12.01%
(Columbia Acorn International Select) | Class I Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.94%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.18% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.12%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 114
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 356
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 617
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,363
1 Year rr_AverageAnnualReturnYear01 22.48%
5 Years rr_AverageAnnualReturnYear05 0.53%
10 Years rr_AverageAnnualReturnYear10 13.28%
(Columbia Acorn International Select) | Class R4 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.94%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.38% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.32%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 134
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 418
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 723
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,590
1 Year rr_AverageAnnualReturnYear01 22.38%
5 Years rr_AverageAnnualReturnYear05 0.50%
10 Years rr_AverageAnnualReturnYear10 13.26%
(Columbia Acorn International Select) | Class R5 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.94%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.23% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.17%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 119
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 372
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 644
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,420
1 Year rr_AverageAnnualReturnYear01 22.39%
5 Years rr_AverageAnnualReturnYear05 0.50%
10 Years rr_AverageAnnualReturnYear10 13.27%
(Columbia Acorn International Select) | Class Y Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.94%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.18% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.12%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 114
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 356
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 617
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,363
1 Year rr_AverageAnnualReturnYear01 22.40%
5 Years rr_AverageAnnualReturnYear05 0.50%
10 Years rr_AverageAnnualReturnYear10 13.27%
(Columbia Acorn International Select) | Class Z Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.94%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.32% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.26%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 128
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 400
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 692
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,523
Annual Return 2003 rr_AnnualReturn2003 41.79%
Annual Return 2004 rr_AnnualReturn2004 24.14%
Annual Return 2005 rr_AnnualReturn2005 15.98%
Annual Return 2006 rr_AnnualReturn2006 36.27%
Annual Return 2007 rr_AnnualReturn2007 21.86%
Annual Return 2008 rr_AnnualReturn2008 (42.10%)
Annual Return 2009 rr_AnnualReturn2009 31.52%
Annual Return 2010 rr_AnnualReturn2010 21.89%
Annual Return 2011 rr_AnnualReturn2011 (9.76%)
Annual Return 2012 rr_AnnualReturn2012 22.42%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel 2nd quarter 2009:
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 23.44%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel 3rd quarter 2008:
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (24.76%)
1 Year rr_AverageAnnualReturnYear01 22.42%
5 Years rr_AverageAnnualReturnYear05 0.50%
10 Years rr_AverageAnnualReturnYear10 13.27%
(Columbia Acorn International Select) | Class Z Shares | returns after taxes on distributions
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 18.84%
5 Years rr_AverageAnnualReturnYear05 (0.32%)
10 Years rr_AverageAnnualReturnYear10 12.72%
(Columbia Acorn International Select) | Class Z Shares | returns after taxes on distributions and sale of Fund shares
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.81%
5 Years rr_AverageAnnualReturnYear05 0.25%
10 Years rr_AverageAnnualReturnYear10 11.92%
(Columbia Acorn Select)
  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds. More information about these and other discounts is available from your financial advisor, in the Choosing a Share Class section beginning on page 21 of this prospectus and in Appendix S to the Statement of Additional Information under Sales Charge Waivers beginning on page S-1. The Fund no longer accepts investments from new or existing investors in Class B shares. Class I shares are generally available only to other Columbia Funds.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 15% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 15.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

  • you invest $10,000 in Class A, Class B, Class C, Class I, Class R4, Class R5, Class Y or Class Z shares of the Fund for the periods indicated,

  • your investment has a 5% return each year, and

  • the Fund's total annual operating expenses remain the same as shown in the table above.

Based on the assumptions listed above, your costs would be:
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock

Remember this is an example only. Your actual costs may be higher or lower.

Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of companies with market capitalizations under $20 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $20 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $20 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $20 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $20 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Fund invests the majority of its assets in U.S. companies, but also may invest up to 33% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Colombia).

The Fund takes advantage of the Investment Manager's research and stock-picking capabilities to invest in a limited number of companies (generally between 30-60), offering the potential to provide above-average growth over time.

The Investment Manager typically seeks companies with:

  • A strong business franchise that offers growth potential.

  • Products and services that give the company a competitive advantage.

  • A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Fund may also invest in companies that the Investment Manager believes have good operational fundamentals but that the Investment Manager believes are undervalued due to negative investor sentiment related to company-specific or market-related conditions. Investments in turnaround and development stage companies may also be made when the Investment Manager believes potential returns outweigh risks of losses.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

  • Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

  • Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

  • Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller companies may not be widely followed by the investment community, which can lower the demand for their stocks.

  • Sector Risk – At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

  • Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.

    Operational and Settlement Risks of Foreign Securities. The Fund's foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies ("foreign sub-custodians"), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

    Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer's securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

  • Emerging Market Securities Risk – Securities issued by foreign governments or companies in emerging market countries, like Russia and those in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.

    Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.

    Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not be traded internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country's economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

    Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in Russia.

  • Opportunistic Investing Risk - Undervalued securities involve the risk that they may never reach their expected full market value, either because the market fails to recognize the security's intrinsic worth or the expected value was misgauged. Undervalued securities also may decline in price even though the Investment Manager believes they are already undervalued. Turnaround companies may never improve their fundamentals, may take much longer than expected to improve, or may improve much less than expected. Development stage companies could fail to develop and deplete their assets, resulting in large percentage losses.

  • Currency Risk – Securities denominated in non-U.S. dollar currencies are subject to the risk that, for example, if the value of a foreign currency were to decline against the U.S. dollar, such decline would reduce the U.S. dollar value of any securities held by the Fund denominated in that currency.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart below and table on the following page show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The inception date for the Fund's Class I shares is September 27, 2010 and the inception date for the Fund's Class R4, Class R5 and Class Y shares is November 8, 2012. The returns shown for these share classes include the returns of the Fund's Class Z shares for periods prior to their inception dates. Except for differences in expenses, these share classes have annual returns substantially similar to those of Class Z shares, because all classes of the Fund's shares invest in the same portfolio of securities.

The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 800.345.6611
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.columbiamanagement.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year

[15]
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock 

Best and Worst Quarterly Returns During this Period

Best:    2nd quarter 2009:       28.11%

Worst:   4th quarter 2008:      -30.14%
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Return as of December 31, 2012

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Class Z shares and will vary for other share classes.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

The table compares the Fund's returns for each period with those of the Standard & Poor's (S&P) MidCap 400® Index, the Fund's primary benchmark, and the S&P 500® Index. The S&P MidCap 400® Index is a market value-weighted index that tracks the performance of 400 mid-cap U.S. companies. The S&P 500® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. Although the Fund typically invests in companies with market capitalizations under $20 billion at the time of investment, the comparison to the S&P 500® Index is presented to show performance against a widely recognized market index.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown only for Class Z shares and will vary for other share classes.
(Columbia Acorn Select) | S&P 500® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.00%
5 Years rr_AverageAnnualReturnYear05 1.66%
10 Years rr_AverageAnnualReturnYear10 7.10%
(Columbia Acorn Select) | S&P MidCap 400® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 17.88%
5 Years rr_AverageAnnualReturnYear05 5.15%
10 Years rr_AverageAnnualReturnYear10 10.53%
(Columbia Acorn Select) | Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Management fees rr_ManagementFeesOverAssets 0.83%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.27% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.35%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 705
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 978
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,272
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,105
1 Year rr_AverageAnnualReturnYear01 10.15%
5 Years rr_AverageAnnualReturnYear05 (1.14%)
10 Years rr_AverageAnnualReturnYear10 7.64%
(Columbia Acorn Select) | Class B Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 5.00% [2]
Management fees rr_ManagementFeesOverAssets 0.83%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other expenses rr_OtherExpensesOverAssets 0.37% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.95%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 698
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 912
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,252
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,120
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 198
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 612
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,052
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,120
1 Year rr_AverageAnnualReturnYear01 11.11%
5 Years rr_AverageAnnualReturnYear05 (0.95%)
10 Years rr_AverageAnnualReturnYear10 7.57%
(Columbia Acorn Select) | Class C Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [3]
Management fees rr_ManagementFeesOverAssets 0.83%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.25% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 2.08%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 311
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 652
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,119
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,410
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 211
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 652
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,119
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,410
1 Year rr_AverageAnnualReturnYear01 14.93%
5 Years rr_AverageAnnualReturnYear05 (0.76%)
10 Years rr_AverageAnnualReturnYear10 7.44%
(Columbia Acorn Select) | Class I Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.83%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.12% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.95%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 97
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 303
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 525
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,166
1 Year rr_AverageAnnualReturnYear01 17.26%
5 Years rr_AverageAnnualReturnYear05 0.39%
10 Years rr_AverageAnnualReturnYear10 8.65%
(Columbia Acorn Select) | Class R4 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.83%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.32% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 117
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 365
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 633
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,398
1 Year rr_AverageAnnualReturnYear01 17.11%
5 Years rr_AverageAnnualReturnYear05 0.32%
10 Years rr_AverageAnnualReturnYear10 8.61%
(Columbia Acorn Select) | Class R5 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.83%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.17% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.00%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 102
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 318
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 552
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,225
1 Year rr_AverageAnnualReturnYear01 17.15%
5 Years rr_AverageAnnualReturnYear05 0.33%
10 Years rr_AverageAnnualReturnYear10 8.62%
(Columbia Acorn Select) | Class Y Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.83%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.12% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.95%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 97
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 303
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 525
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,166
1 Year rr_AverageAnnualReturnYear01 17.14%
5 Years rr_AverageAnnualReturnYear05 0.33%
10 Years rr_AverageAnnualReturnYear10 8.62%
(Columbia Acorn Select) | Class Z Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.83%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.24% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.07%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 109
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 340
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 590
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,306
Annual Return 2003 rr_AnnualReturn2003 30.61%
Annual Return 2004 rr_AnnualReturn2004 18.58%
Annual Return 2005 rr_AnnualReturn2005 11.08%
Annual Return 2006 rr_AnnualReturn2006 19.68%
Annual Return 2007 rr_AnnualReturn2007 9.20%
Annual Return 2008 rr_AnnualReturn2008 (49.18%)
Annual Return 2009 rr_AnnualReturn2009 66.17%
Annual Return 2010 rr_AnnualReturn2010 22.88%
Annual Return 2011 rr_AnnualReturn2011 (16.37%)
Annual Return 2012 rr_AnnualReturn2012 17.15%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel 2nd quarter 2009:
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 28.11%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel 4th quarter 2008:
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (30.14%)
1 Year rr_AverageAnnualReturnYear01 17.15%
5 Years rr_AverageAnnualReturnYear05 0.33%
10 Years rr_AverageAnnualReturnYear10 8.62%
(Columbia Acorn Select) | Class Z Shares | returns after taxes on distributions
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 15.80%
5 Years rr_AverageAnnualReturnYear05 (0.10%)
10 Years rr_AverageAnnualReturnYear10 8.21%
(Columbia Acorn Select) | Class Z Shares | returns after taxes on distributions and sale of Fund shares
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 12.87%
5 Years rr_AverageAnnualReturnYear05 0.20%
10 Years rr_AverageAnnualReturnYear10 7.58%
(Columbia Acorn USA)
  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds. More information about these and other discounts is available from your financial advisor, in the Choosing a Share Class section beginning on page 18 of this prospectus and in Appendix S to the Statement of Additional Information under Sales Charge Waivers beginning on page S-1. The Fund no longer accepts investments from new or existing investors in Class B shares. Class I shares are generally available only to other Columbia Funds.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 14% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 14.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

  • you invest $10,000 in Class A, Class B, Class C, Class I, Class R4, Class R5, Class Y or Class Z shares of the Fund for the periods indicated,

  • your investment has a 5% return each year, and

  • the Fund's total annual operating expenses remain the same as shown in the table above.

Based on the assumptions listed above, your costs would be:
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock

Remember this is an example only. Your actual costs may be higher or lower.

Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in U.S. companies.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $5 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $5 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Investment Manager typically seeks companies with:

  • A strong business franchise that offers growth potential.

  • Products and services that give the company a competitive advantage.

  • A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

  • Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

  • Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

  • Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller companies may not be widely followed by the investment community, which can lower the demand for their stocks.

  • Sector Risk – At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart below and table on the following page show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The inception date for the Fund's Class I shares is September 27, 2010; and the inception date for the Fund's Class R4, Class R5 and Class Y shares is November 8, 2012. The returns shown for these share classes include the returns of the Fund's Class Z shares for periods prior to their inception dates. Except for differences in expenses, these classes of shares have annual returns substantially similar to those of Class Z shares, because all classes of the Fund's shares invest in the same portfolio of securities.

The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 800.345.6611
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.columbiamanagement.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year

[16]
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock 

Best and Worst Quarterly Returns During this Period

Best:    3rd quarter 2009:       23.55%

Worst:   4th quarter 2008:      -27.96%
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Return as of December 31, 2012

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Class Z shares and will vary for other share classes.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

The table compares the Fund's returns for each period with those of the Russell 2000 Index. This index measures the performance of the 2,000 smallest companies in the Russell 3000 Index, which represents approximately 10% of the total market capitalization of the Russell 3000 Index.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown only for Class Z shares and will vary for other share classes.
(Columbia Acorn USA) | Russell 2000 Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.35%
5 Years rr_AverageAnnualReturnYear05 3.56%
10 Years rr_AverageAnnualReturnYear10 9.72%
(Columbia Acorn USA) | Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Management fees rr_ManagementFeesOverAssets 0.86%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.27% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.38%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 707
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 987
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,287
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,137
1 Year rr_AverageAnnualReturnYear01 11.86%
5 Years rr_AverageAnnualReturnYear05 2.17%
10 Years rr_AverageAnnualReturnYear10 9.39%
(Columbia Acorn USA) | Class B Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 5.00% [2]
Management fees rr_ManagementFeesOverAssets 0.86%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other expenses rr_OtherExpensesOverAssets 0.48% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 2.09%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 712
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 955
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,324
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,239
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 212
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 655
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,124
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,239
1 Year rr_AverageAnnualReturnYear01 12.87%
5 Years rr_AverageAnnualReturnYear05 2.38%
10 Years rr_AverageAnnualReturnYear10 9.33%
(Columbia Acorn USA) | Class C Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [3]
Management fees rr_ManagementFeesOverAssets 0.86%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.19% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 2.05%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 308
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 643
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,103
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,379
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 208
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 643
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,103
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,379
1 Year rr_AverageAnnualReturnYear01 16.82%
5 Years rr_AverageAnnualReturnYear05 2.59%
10 Years rr_AverageAnnualReturnYear10 9.22%
(Columbia Acorn USA) | Class I Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.86%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.11% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.97%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 99
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 309
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 536
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,190
1 Year rr_AverageAnnualReturnYear01 19.10%
5 Years rr_AverageAnnualReturnYear05 3.71%
10 Years rr_AverageAnnualReturnYear10 10.42%
(Columbia Acorn USA) | Class R4 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.86%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.31% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.17%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 119
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 372
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 644
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,420
1 Year rr_AverageAnnualReturnYear01 18.97%
5 Years rr_AverageAnnualReturnYear05 3.67%
10 Years rr_AverageAnnualReturnYear10 10.40%
(Columbia Acorn USA) | Class R5 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.86%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.16% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.02%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 104
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 325
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 563
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,248
1 Year rr_AverageAnnualReturnYear01 18.97%
5 Years rr_AverageAnnualReturnYear05 3.67%
10 Years rr_AverageAnnualReturnYear10 10.40%
(Columbia Acorn USA) | Class Y Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.86%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.11% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 0.97%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 99
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 309
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 536
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,190
1 Year rr_AverageAnnualReturnYear01 18.97%
5 Years rr_AverageAnnualReturnYear05 3.67%
10 Years rr_AverageAnnualReturnYear10 10.40%
(Columbia Acorn USA) | Class Z Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.86%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.29% [4]
Total annual Fund operating expenses rr_ExpensesOverAssets 1.15%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 117
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 365
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 633
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,398
Annual Return 2003 rr_AnnualReturn2003 47.13%
Annual Return 2004 rr_AnnualReturn2004 20.62%
Annual Return 2005 rr_AnnualReturn2005 12.98%
Annual Return 2006 rr_AnnualReturn2006 8.28%
Annual Return 2007 rr_AnnualReturn2007 3.46%
Annual Return 2008 rr_AnnualReturn2008 (39.22%)
Annual Return 2009 rr_AnnualReturn2009 41.49%
Annual Return 2010 rr_AnnualReturn2010 23.16%
Annual Return 2011 rr_AnnualReturn2011 (4.95%)
Annual Return 2012 rr_AnnualReturn2012 18.98%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel 3rd quarter 2009:
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 23.55%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel 4th quarter 2008:
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (27.96%)
1 Year rr_AverageAnnualReturnYear01 18.98%
5 Years rr_AverageAnnualReturnYear05 3.67%
10 Years rr_AverageAnnualReturnYear10 10.40%
(Columbia Acorn USA) | Class Z Shares | returns after taxes on distributions
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 17.50%
5 Years rr_AverageAnnualReturnYear05 3.28%
10 Years rr_AverageAnnualReturnYear10 9.97%
(Columbia Acorn USA) | Class Z Shares | returns after taxes on distributions and sale of Fund shares
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 14.21%
5 Years rr_AverageAnnualReturnYear05 3.12%
10 Years rr_AverageAnnualReturnYear10 9.25%
(Columbia Thermostat Fund)
  
Risk/Return: rr_RiskReturnAbstract  
Objective [Heading] rr_ObjectiveHeading

Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock

The Fund seeks long-term capital appreciation.

Expense [Heading] rr_ExpenseHeading

Fees and Expenses of the Fund
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds. More information about these and other discounts is available from your financial advisor, in the Choosing a Share Class section beginning on page 34 of this prospectus and in Appendix S to the Statement of Additional Information under Sales Charge Waivers beginning on page S-1.

The Fund no longer accepts investments from new or existing investors in Class B shares.
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text] rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination 2014-04-30
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock

The Fund will indirectly bear the expenses associated with portfolio turnover of the underlying Portfolio Funds in which the Fund invests. Each Portfolio Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A Portfolio Fund's higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when its shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 109% of the average value of its portfolio.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 109.00%
Expense Breakpoint Discounts [Text] rr_ExpenseBreakpointDiscounts You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible Columbia Funds.
Expense Breakpoint, Minimum Investment Required [Amount] rr_ExpenseBreakpointMinimumInvestmentRequiredAmount 50,000
Expense Example [Heading] rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

  • you invest $10,000 in Class A, Class B, Class C, Class R4, Class R5, Class Y or Class Z shares of the Fund for the periods indicated,

  • your investment has a 5% return each year, and

  • the Fund's total annual operating expenses remain the same as shown in the table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire on April 30, 2014, they are only reflected in the 1 year example and the first year of the 3, 5 and 10 year examples.

Based on the assumptions listed above, your costs would be:
Expense Example Closing [Text Block] rr_ExpenseExampleClosingTextBlock

Remember this is an example only. Your actual costs may be higher or lower.

Strategy [Heading] rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock

The Fund pursues its investment objective by investing in other mutual funds. As a "fund of funds," under normal circumstances, the Fund allocates at least 95% of its net assets (stock/bond assets) among a selected group of stock and bond mutual funds (Portfolio Funds) according to the current level of Standard & Poor's (S&P) 500® Index. Generally, when the S&P 500® Index goes up in relation to predetermined ranges set by Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), the Fund sells a portion of its stock funds and invests more in the bond funds and when the S&P 500® Index goes down in relation to the ranges, the Fund increases its investment in the stock funds. Under normal circumstances, the Fund may invest up to 5% of net assets plus any cash received that day in cash, high quality short-term paper and government securities.

Many asset allocation funds typically move assets from stocks to bonds when the market goes up, and from bonds to stocks when the market goes down. Most asset allocation funds are run by sophisticated investment professionals, who make subjective decisions based on economic and financial data and complex graphs of market behavior. By contrast, the day-to-day investment decisions for the Fund are made according to a single predetermined rule. The temperature in your house is run by a single rule: your thermostat turns on the furnace if your house is too cold or turns on the air conditioner if your house is too warm. This Fund works the same way, so it is named Columbia Thermostat Fund.

Because the Fund invests according to a pre-set program, there is no need for subjective day-to-day management. Although another successful asset allocation strategy might do better than the Fund, the Fund is designed for those who doubt the wisdom of trying to "time" the market and are unsure of the long-term trend of the stock market. The Fund takes psychology out of investing; it avoids the temptation to buy more stocks because the stock market is currently going up or to sell stocks because the market is declining. The Fund operates continuously and substantially automatically, subject to periodic review of the pre-set program by the Investment Manager and the Fund's Board of Trustees. As described more fully below, the Investment Manager has the authority to review the structure and allocation ranges of the stock/bond allocation table and to make any changes considered appropriate.

The Investment Manager chooses the Portfolio Funds to provide participation in the major sectors of the stock and bond markets. If you believe that the stock market will tend to go up most of the time, then you should probably own a fully invested stock fund and use a buy-and-hold strategy. Buy-and-hold was an excellent strategy in the 1982-1999 bull market. However, there have been long periods in the past when buy-and-hold was not the best strategy, such as 1930-1954 and 1969-1981, when the market fluctuated but did not make significant new highs. The Fund may be a good investment choice for you if you believe that the market may fluctuate in a trading range for many years, that a remarkable bull market ended early in 2000 and that the market may not reach significant new highs for many years.

The Fund invests its stock/bond assets among the Portfolio Funds according to an asset allocation table. The current allocation table is set forth below.

Stock/Bond Allocation Table

                 

  

  

How the Fund will Invest the Stock/Bond Assets

 

Level of the S&P 500® Index

  

Stock Percentage

 

 

Bond Percentage

 

over 1750

  

 

10

% 

 

 

90

% 

over 1700-1750

  

 

15

% 

 

 

85

% 

over 1650-1700

  

 

20

% 

 

 

80

% 

over 1600-1650

  

 

25

% 

 

 

75

% 

over 1550-1600

  

 

30

% 

 

 

70

% 

over 1500-1550

  

 

35

% 

 

 

65

% 

over 1450-1500

  

 

40

% 

 

 

60

% 

over 1400-1450

  

 

45

% 

 

 

55

% 

over 1350-1400

  

 

50

% 

 

 

50

% 

over 1300-1350

  

 

55

% 

 

 

45

% 

over 1250-1300

  

 

60

% 

 

 

40

% 

over 1200-1250

  

 

65

% 

 

 

35

% 

over 1150-1200

  

 

70

% 

 

 

30

% 

over 1100-1150

  

 

75

% 

 

 

25

% 

over 1050-1100

  

 

80

% 

 

 

20

% 

over 1000-1050

  

 

85

% 

 

 

15

% 

1000 and under

  

 

90

% 

 

 

10

% 

When the S&P 500® Index moves into a new band on the table, the Fund promptly will rebalance the stock/bond mix to reflect the new S&P 500® Index price level by redeeming shares of some Portfolio Funds and purchasing shares of other Portfolio Funds. The only exception will be a "31-day Rule"; in order to reduce taxable events, after the Fund has increased its percentage allocation to either stock funds or bond funds, it will not decrease that allocation for at least 31 days. Following a change in the Fund's stock/bond mix, if the S&P 500® Index remains within the same band for a while, normal market fluctuations will change the values of the Fund's holdings of stock Portfolio Funds and bond Portfolio Funds. The Investment Manager will invest cash flows from sales (or redemptions) of Fund shares to bring the stock/bond mix back toward the allocation percentages for that S&P 500® Index band. For example, if the S&P 500® Index is in the 1150-1200 band, and the value of the holdings of the stock Portfolio Funds has dropped to 68% of the value of the holdings of all Portfolio Funds, the Investment Manager would invest new cash in the stock Portfolio Funds (or cash for redemptions would come from the bond Portfolio Funds). If the 31-day Rule is in effect, the Investment Manager will invest new cash at the stock/bond percentage allocation as of the latest rebalancing.

As an illustrative example, suppose the following:

         

Date

  

Level of the S&P 500® Index

  

How the Fund will invest the Stock/Bond Assets

Nov. 1

  

We begin when the market is 1380

  

50% stocks, 50% bonds

Dec. 1

  

The S&P 500® goes to 1401

  

rebalance 45% stocks, 55% bonds

Dec. 6

  

The S&P 500® drops back to 1390

  

no reversal for 31 days

Jan. 2

  

The S&P 500® is at 1352

  

rebalance 50% stocks, 50% bonds

Jan. 20

  

The S&P 500® drops to 1349

  

rebalance 55% stocks, 45% bonds
 

  

The market has made a continuation move by going through a second action level, not a reversal move, so the 31-day Rule does not apply in this case.

Jan. 30

  

The S&P 500® goes up to 1355

  

no reversal for 31 days

Feb. 20

  

The S&P 500® is at 1360

  

rebalance 50% stocks, 50% bonds

The following table shows the seven stock Portfolio Funds and three bond Portfolio Funds that the Fund currently uses in its "fund of funds" structure and the current allocation percentage for each Portfolio Fund within the stock or bond category. As described more fully below, the Investment Manager may substitute or add additional Portfolio Funds at any time, including funds introduced after the date of this prospectus. The allocation percentage within each stock/bond category is achieved by rebalancing the investments within the category whenever the S&P 500® Index moves into a new band on the allocation table, subject to the 31-day Rule described above. The Fund does not liquidate its investment in one Portfolio Fund in order to invest in another Portfolio Fund except in connection with a rebalancing due to a move of the S&P 500® Index into a new band (or due to a change by the Investment Manager in the stock/bond allocation table to the Portfolio Funds or to the relative allocation among them). Until a subsequent rebalancing, the Fund's investments in, and redemptions from, the stock Portfolio Funds or the bond Portfolio Funds are allocated among the Portfolio Funds in a manner that will reduce any deviation of the relative values of the Fund's holdings of the Funds from the allocation percentages shown below.

Allocation of Stock/Bond Assets Within Asset Classes

             

Stock Funds

  

Type of Fund

  

Allocation

 

Columbia Acorn Fund

  

Small/Mid-cap growth

  

 

15

% 

Columbia Acorn Select

  

Mid-cap growth

  

 

10

% 

Columbia Acorn International

  

Small/Mid-cap international growth

  

 

20

% 

Columbia Dividend Income Fund

  

Large-cap value

  

 

20

% 

Columbia Large Cap Enhanced Core Fund

  

Large-cap blend

  

 

10

% 

Columbia Contrarian Core Fund

  

Large-cap blend

  

 

15

% 

Columbia Select Large Cap Growth Fund

  

Large-cap growth

  

 

10

% 

Total

  

  

  

 

100

% 

             

Bond Funds

  

Type of Fund

  

Allocation

 

Columbia Intermediate Bond Fund

  

Intermediate-term bond

  

 

30

% 

Columbia Income Opportunities Fund

  

High-yield bond

  

 

30

% 

Columbia Short Term Bond Fund

  

Short term bond

  

 

40

% 

Total

  

  

  

 

100

% 

The Investment Manager has the authority to review the Portfolio Funds and the relative stock/bond allocation percentages among them and to make any changes considered appropriate.

Each of the Portfolio Funds is currently managed by the Investment Manager or its affiliates. The Fund does not pay any sales load on its purchases of shares of the Portfolio Funds. On an annual basis, or on an "emergency" basis if necessary, the Investment Manager reviews the structure, allocation percentages and Portfolio Funds and makes any changes considered appropriate. The Investment Manager typically addresses the following questions:

  • Should the stock/bond allocation table be revised (perhaps because the stock market has made a long-term move outside of the bands set forth above)?
  • Should there be a change in the Portfolio Funds or should there be a change in the percentage allocations among the stock/bond funds (perhaps because of a change of portfolio managers, change of investment style, change in relative valuation or a reorganization of a Portfolio Fund)?

Any such changes by the Investment Manager are expected to be infrequent.
Risk [Heading] rr_RiskHeading

Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock

  • Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

  • Allocation Risk – The Fund uses an asset allocation strategy in pursuit of its investment objective. There is a risk that the Fund's allocation among asset classes or investments will cause the Fund's shares to lose value or cause the Fund to underperform other funds with similar investment objectives, or that the investments themselves will not produce the returns expected.

  • Investing in Other Funds Risk – The performance of the underlying fund(s) in which the Fund invests could be adversely affected if other entities that invest in the same underlying fund(s) make relatively large investments or redemptions in the underlying fund(s). In addition, because the expenses and costs of the underlying fund(s) are shared by investors in the underlying fund, redemptions by other investors in the underlying fund could result in decreased economies of scale and increased operating expenses for the underlying fund. The Fund, and its shareholders, indirectly bear a portion of the expenses of the underlying fund(s). These transactions might also result in higher brokerage, tax or other costs for the Fund. This risk may be particularly important when one investor owns a substantial portion of any underlying fund. In addition, the Investment Manager has the authority to change the underlying fund(s) in which the Fund invests or to change the percentage of the Fund's investments allocated to each underlying fund. If an underlying fund pays fees to the Investment Manager or its affiliates, such as advisory fees, this could result in the Investment Manager having a potential conflict of interest in selecting the underlying fund(s) in which the Fund invests or in determining the percentage of the Fund's investments allocated to each underlying fund. In addition, the underlying funds are themselves subject to Investment Strategy Risk.

The Fund is subject indirectly to the following risks of the Portfolio Funds:

  • Market Risk – Market risk refers to the possibility that the market values of securities that a Portfolio Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Portfolio Fund. Accordingly, an investment in a Portfolio Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Portfolio Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

  • Interest Rate Risk – Debt securities are subject to interest rate risk. In general, if prevailing interest rates rise, the values of debt securities will tend to fall, and if interest rates fall, the values of debt securities will tend to rise. Changes in the value of a debt security usually will not affect the amount of income a Portfolio Fund receives from it but may affect the value of the Portfolio Fund's shares. Interest rate risk is generally greater for debt securities with longer maturities/durations.

  • Credit Risk – Credit risk applies to most debt securities, but is generally less of a factor for obligations backed by the "full faith and credit" of the U.S. Government. A Portfolio Fund could lose money if the issuer of a debt security owned by the Fund is unable or perceived to be unable to pay interest or repay principal when it becomes due. Various factors could affect the issuer's actual or perceived willingness or ability to make timely interest or principal payments, including changes in the issuer's financial condition or in general economic conditions. Debt securities backed by an issuer's taxing authority may be subject to legal limits on the issuer's power to increase taxes or otherwise to raise revenue, or may be dependent on legislative appropriation or government aid. Certain debt securities are backed only by revenues derived from a particular project or source, rather than by an issuer's taxing authority, and thus may have a greater risk of default.

  • Low and Below Investment Grade Securities Risk – Debt securities with the lowest investment grade rating (e.g., BBB by Standard & Poor's, a division of the McGraw-Hill Companies, Inc. (S&P), or Fitch, Inc. (Fitch) or Baa by Moody's Investors Service, Inc. (Moody's)), or that are below investment grade (which are commonly referred to as "junk bonds") (e.g., BB or below by S&P or Fitch or Ba by Moody's) and unrated securities of comparable quality are more speculative than securities with higher ratings and may experience greater price fluctuations. These securities tend to be more sensitive to credit risk than higher-rated securities, particularly during a downturn in the economy, which is more likely to weaken the ability of the issuers to make principal and interest payments on these securities. These securities typically pay a premium – a higher interest rate or yield – because of the increased risk of loss, including default. These securities also are generally less liquid than higher-rated securities. The securities ratings provided by Moody's, S&P and Fitch are based on analyses by these ratings agencies of the credit quality of the securities and may not take into account every risk related to whether interest or principal will be timely repaid.

  • Value Securities Risk – Value securities are securities of companies that may have experienced, for example, adverse business, industry or other developments or may be subject to special risks that have caused the securities to be out of favor and, in turn, potentially undervalued. The market value of a portfolio security may not meet the Investment Manager's future value assessment of that security, or may decline. There is also a risk that it may take longer than expected for the value of these investments to rise to the believed value. In addition, value securities, at times, may not perform as well as growth securities or the stock market in general, and may be out of favor with investors for varying periods of time.

  • Growth Securities Risk – Because growth securities typically trade at a higher multiple of earnings than other types of securities, the market values of growth securities may be more sensitive to changes in current or expected earnings than the market values of other types of securities. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time.

  • Sector Risk – At times, certain Portfolio Funds may have a significant portion of their assets invested in securities of companies conducting business in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Portfolio Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

  • Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Portfolio Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees and other fees are also generally higher for foreign securities. The Portfolio Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.

    Operational and Settlement Risks of Foreign Securities. The Fund's foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies ("foreign sub-custodians"), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

    Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer's securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

  • Emerging Market Securities Risk – Securities issued by foreign governments or companies in emerging market countries, like Russia and those in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.

    Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.

    Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not be traded internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country's economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

    Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in Russia.

  • Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller companies may not be widely followed by the investment community, which can lower the demand for their stocks.

  • U.S. Government Obligations Risk – While U.S. Treasury obligations are backed by the "full faith and credit" of the U.S. Government, such securities are nonetheless subject to credit risk (i.e., the risk that the U.S. Government may be, or may be perceived to be, unable or unwilling to honor its financial obligations, such as making payments). Securities issued or guaranteed by federal agencies or authorities and U.S. Government-sponsored instrumentalities or enterprises may or may not be backed by the full faith and credit of the U.S. Government. For example, securities issued by the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association and the Federal Home Loan Banks are neither insured nor guaranteed by the U.S. Government. These securities may be supported by the ability to borrow from the U.S. Treasury or only by the credit of the issuing agency, authority, instrumentality or enterprise and, as a result, are subject to greater credit risk than securities issued or guaranteed by the U.S. Treasury.

  • Derivatives Risk – Derivatives are financial contracts whose values are, for example, based on (or "derived" from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as LIBOR) or market indices (such as the S&P 500® Index). Derivatives involve special risks and may result in losses or may limit a Portfolio Fund's potential gain from favorable market movements. Derivative strategies often involve leverage, which may exaggerate a loss, potentially causing a Portfolio Fund to lose more money than it would have lost had it invested in the underlying security or other asset. The values of derivatives may move in unexpected ways, especially in unusual market conditions, and may result in increased volatility, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks arise from a Portfolio Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Portfolio Fund's derivative positions at times when the Portfolio Fund might wish to terminate or to sell such positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. A Portfolio Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. U.S. federal legislation has recently been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. While the ultimate impact is not yet clear, these changes could restrict and/or impose significant costs or other burdens upon the Fund's participation in derivatives transactions. For more information on the risks of derivative investments and strategies, see the Statement of Additional Information.

  • Convertible Securities Risk – Certain Portfolio Funds invest in convertible securities, which are subject to the usual risks associated with debt securities, such as interest rate risk and credit risk. Convertible securities also react to changes in the value of the common stock into which they convert. Because the value of a convertible security can be influenced by both interest rates and the common stock's market movements, a convertible security generally is not as sensitive to interest rates as a similar debt security, and generally will not vary in value in response to other factors to the same extent as the underlying common stock. In the event of a liquidation of the issuing company, holders of convertible securities would typically be paid before the company's common stockholders but after holders of any senior debt obligations of the company. A Portfolio Fund may be forced to convert a convertible security before it otherwise would choose to do so, which may decrease the Portfolio Fund's return.

  • Technology Sector Risk – Companies in the technology sector are subject to significant competitive pressures, such as aggressive pricing of their products or services, new market entrants, competition for market share, short product cycles due to an accelerated rate of technological developments and the potential for limited earnings and/or falling profit margins. These companies also face the risks that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. These factors can affect the profitability of technology companies and, as a result, the value of their securities. Also, patent protection is integral to the success of many companies in the technology sector, and profitability can be affected materially by, among other things, the cost of obtaining (or failing to obtain) patent approvals, the cost of litigating patent infringement and the loss of patent protection for products (which significantly increases pricing pressures and can materially reduce profitability with respect to such products). In addition, many technology companies have limited operating histories. Prices of these companies' securities historically have been more volatile than other securities, especially over the short term. Because certain Portfolio Funds invest a significant portion of their net assets in the equity securities of technology companies, a Portfolio Fund's price may be more volatile than a fund that is invested in a more diverse range of market sectors.

  • Health Care Sector Risk - Companies in the health care sector are subject to extensive government regulation. Their profitability can be affected significantly and adversely by restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, an increased emphasis on outpatient and other alternative services and other factors. Patent protection is integral to the success of companies in the health care sector, and profitability can be affected materially by, among other things, the cost of obtaining (or failing to obtain) patent approvals, the cost of litigating patent infringement and the loss of patent protection for medical products (which significantly increases pricing pressures and can materially reduce profitability with respect to such products). Companies in the health care sector also potentially are subject to extensive product liability and other similar litigation. Companies in the health care sector are affected by the rising cost of medical products and services, and the effects of such rising costs can be particularly pronounced for companies that are dependent on a relatively limited number of products or services. Medical products also frequently become obsolete due to industry innovation or other causes. Because certain Portfolio Funds invest a significant portion of their net assets in the equity securities of health care companies, a Portfolio Fund's price may be more volatile than a fund that is invested in a more diverse range of market sectors.

  • Dollar Rolls Risk – Dollar rolls are transactions in which a Portfolio Fund sells securities to counterparty and simultaneously agrees to purchase those or similar securities in the future at a predetermined price. Dollar rolls involve the risk that the market value of the securities the Portfolio Fund is obligated to repurchase may decline below the repurchase price, or that the counterparty may default on its obligations. These transactions may also increase the Portfolio Fund's portfolio turnover rate. If the Portfolio Fund reinvests the proceeds of the security sold, the Portfolio Fund will also be subject to the risk that the investments purchased with such proceeds will decline in value (a form of leverage risk).

  • Mortgage-Backed Securities Risk – The value of a Portfolio Fund's mortgage-backed securities may be affected by, among other things, changes or perceived changes in: interest rates, factors concerning the interests in and structure of the issuer or the originator of the mortgages, the creditworthiness of the entities that provide any supporting letters of credit, surety bonds or other credit enhancements, or the market's assessment of the quality of underlying assets. Mortgage backed securities represent interests in, or are backed by, pools of mortgages from which payments of interest and principal (net of fees paid to the issuer or guarantor of the securities) are distributed to the holders of the mortgage-backed securities. Mortgage-backed securities can have a fixed or an adjustable rate. Payment of principal and interest on some mortgage-backed securities (but not the market value of the securities themselves) may be guaranteed (i) by the full faith and credit of the U.S. Government (in the case of securities guaranteed by the Government National Mortgage Association) or (ii) by its agencies, authorities, enterprises or instrumentalities (in the case of securities guaranteed by the Federal National Mortgage Association (FNMA) or the Federal Home Loan Mortgage Corporation (FHLMC)), which are not insured or guaranteed by the U.S. Government (although FNMA and FHLMC may be able to access capital from the U.S. Treasury to meet their obligations under such securities). Mortgage backed securities issued by non-governmental issuers (such as commercial banks, savings and loan institutions, private mortgage insurance companies, mortgage bankers and other secondary market issuers) may be supported by various credit enhancements, such as pool insurance, guarantees issued by governmental entities, letters of credit from a bank or senior/subordinated structures, and may entail greater risk than obligations guaranteed by the U.S. Government, whether or not such obligations are guaranteed by the private issuer. Mortgage-backed securities are subject to prepayment risk, which is the possibility that the underlying mortgage may be refinanced or prepaid prior to maturity during periods of declining or low interest rates, causing the Portfolio Fund to have to reinvest the money received in securities that have lower yields. In addition, the impact of prepayments on the value of mortgage-backed securities may be difficult to predict and may result in greater volatility. Rising or high interest rates tend to extend the duration of mortgage-backed securities, making them more volatile and more sensitive to changes in interest rates.

  • Asset-Backed Securities Risk – The value of a Portfolio Fund's asset-backed securities may be affected by, among other things, changes in: interest rates, factors concerning the interests in and structure of the issuer or the originator of the receivables, the creditworthiness of the entities that provide any supporting letters of credit, surety bonds or other credit enhancements, or the market's assessment of the quality of underlying assets. Asset-backed securities represent interests in, or are backed by, pools of receivables such as credit card, auto, student and home equity loans. They may also be backed, in turn, by securities backed by these types of loans and others, such as mortgage loans. Asset-backed securities can have a fixed or an adjustable rate. Most asset-backed securities are subject to prepayment risk, which is the possibility that the underlying debt may be refinanced or prepaid prior to maturity during periods of declining or low interest rates, causing the Portfolio Fund to have to reinvest the money received in securities that have lower yields. In addition, the impact of prepayments on the value of asset-backed securities may be difficult to predict and may result in greater volatility. Rising or high interest rates tend to extend the duration of asset-backed securities, making them more volatile and more sensitive to changes in interest rates.

  • Prepayment and Extension Risk – Prepayment and extension risk is the risk that a loan, bond or other security might be called or otherwise converted, prepaid or redeemed before maturity. This risk is primarily associated with asset-backed securities, including mortgage-backed securities and floating rate loans. If a loan or security is converted, prepaid or redeemed before maturity, particularly during a time of declining interest rates or spreads, the portfolio managers may not be able to invest the proceeds in securities or loans providing as high a level of income, resulting in a reduced yield to a Portfolio Fund. Conversely, as interest rates rise or spreads widen, the likelihood of prepayment decreases. The portfolio managers may be unable to capitalize on securities with higher interest rates or wider spreads because the Portfolio Fund's investments are locked in at a lower rate for a longer period of time.

  • Reinvestment Risk – Income from a Portfolio Fund's debt securities portfolio will decline if and when the Portfolio Fund invests the proceeds from matured, traded or called securities in securities with market interest rates that are below the current earnings rate of the Portfolio Fund's portfolio.

  • Liquidity Risk – Illiquid securities are securities that cannot be readily disposed of in the normal course of business. There is a risk that a Portfolio Fund may not be able to sell such securities at the time it desires or without adversely affecting their price.

  • Depositary Receipts Risk – Certain Portfolio Funds may invest in depositary receipts. Some foreign securities are traded in the form of American Depositary Receipts (ADRs). Depositary receipts involve the risks of other investments in foreign securities, including risks associated with investing in the particular country, including the political, regulatory, economic, social and other conditions or events occurring in the country, as well as fluctuations in its currency. In addition, ADR holders may not have all the legal rights of shareholders and may experience difficulty in receiving shareholder communications.

  • Derivatives Risk — Futures Contracts – Certain Portfolio Funds may buy or sell futures. A futures contract is a contract between a buyer (holding the "long" position) and a seller (holding the "short" position) for an asset with delivery deferred until a future date. The buyer agrees to pay a fixed price at the agreed future date and the seller agrees to deliver the asset. The seller hopes that the market price on the delivery date is less than the agreed upon price, while the buyer hopes for the contrary. The liquidity of the futures markets depends on participants entering into offsetting transactions rather than making or taking delivery. To the extent participants decide to make or take delivery, liquidity in the particular futures market could be reduced. Certain futures markets are more liquid than others. In addition, certain futures exchanges often impose a maximum permissible price movement on each futures contract for each trading session. To the extent that a Portfolio Fund trades on such futures exchanges, the Portfolio Fund may be disadvantaged if it is prohibited from executing a trade outside the daily permissible price movement.

  • Changing Distribution Levels Risk – The amount of the distributions paid by certain Portfolio Funds generally depends on the amount of interest and/or dividends received by the Portfolio Fund on the securities it holds. A Portfolio Fund may not be able to pay distributions or may have to reduce its distribution level if the interest and/or dividends the Portfolio Fund receives from its investments decline.

  • Rule 144A Securities Risk — Certain Portfolio Funds may invest significantly in privately placed securities that have not been registered for sale under the Securities Act of 1933 pursuant to Rule 144A (Rule 144A securities) which are determined to be liquid in accordance with procedures adopted by the Portfolio Fund's Board of Trustees. However, an insufficient number of qualified institutional buyers interested in purchasing Rule 144A securities could affect adversely the marketability of such securities and the Portfolio Fund might be unable to dispose of such securities promptly or at reasonable prices. Accordingly, even if determined to be liquid, the Portfolio Fund's holdings of Rule 144A securities may increase the level of Fund illiquidity if eligible buyers become uninterested in buying them. The Portfolio Fund may also have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Additionally, the purchase price and subsequent valuation of restricted and illiquid securities normally reflect a discount, which may be significant, from the market price of comparable securities for which a liquid market exists.

  • Currency Risk – Securities denominated in non-U.S. dollar currencies are subject to the risk that, for example, if the value of a foreign currency were to decline against the U.S. dollar, such decline would reduce the U.S. dollar value of any securities held by a Portfolio Fund denominated in that currency.

  • Frequent Trading Risk – Frequent trading of investments increases the possibility that a Portfolio Fund will realize taxable capital gains (including short-term capital gains, which are generally taxable at higher rates than long-term capital gains for U.S. federal income tax purposes), which could reduce the Portfolio Fund's after-tax returns. Frequent trading can also mean higher brokerage and other transaction costs, which could reduce the Portfolio Fund's returns.

  • Index Risk – A Portfolio Fund's value will generally decline when the performance of its targeted index declines. If a Portfolio Fund is designed to track an index before fees and expenses, the Portfolio Fund cannot purchase other securities that may help offset declines in its index. In addition, because the Portfolio Fund may not hold all issues included in its index, may not always be fully invested, and bears advisory, administrative and other expenses and transaction costs in trading securities, the Portfolio Fund's performance may fail to match the performance of its targeted index, after taking expenses into account. It is not possible to invest directly in an index.

  • Highly Leveraged Transactions Risk – The loans and other securities in which certain Portfolio Funds invest include highly leveraged transactions (e.g., bank loans) whereby the borrower assumes large amounts of debt in order to have the financial resources to attempt to achieve its business objectives. Loans or securities that are part of highly leveraged transactions involve a greater risk (including default and bankruptcy) than other investments.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock

The bar chart below and table on the following page show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The inception date for the Fund's Class A, Class B and Class C shares is March 3, 2003; and the inception date for the Fund's Class R4, Class R5 and Class Y shares is November 8, 2012. The returns shown for these share classes include the returns of the Fund's Class Z shares for periods prior to their inception dates. Except for differences in expenses and sales charges (where applicable), these classes of shares have annual returns substantially similar to those of Class Z shares, because all classes of the Fund's shares invest in the same portfolio of securities.

The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 800.345.6611
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.columbiamanagement.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture The Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year

[17]
Bar Chart Narrative [Text Block] rr_BarChartNarrativeTextBlock

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock 

Best and Worst Quarterly Returns During this Period

Best:    2nd quarter 2009:       19.33%

Worst:   4th quarter 2008:      -19.26%
Performance Table Heading rr_PerformanceTableHeading

Average Annual Total Return as of December 31, 2012

Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).
Performance Table One Class of after Tax Shown [Text] rr_PerformanceTableOneClassOfAfterTaxShown The after-tax returns are shown only for Class Z shares and will vary for other share classes.
Performance Table Narrative rr_PerformanceTableNarrativeTextBlock

The table compares the Fund's returns for each period with those of the S&P 500® Index, the Fund's primary benchmark for equity securities, the Barclays U.S. Aggregate Bond Index, the Fund's primary benchmark for debt securities, the Lipper Flexible Portfolio Funds Index and a 50/50 Blended Benchmark. The S&P 500® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. The Barclays U.S. Aggregate Bond Index is a market value-weighted index that tracks the daily price, coupon, pay-downs, and total return performance of fixed-rate, publicly placed, dollar-denominated, and non-convertible investment grade debt issues with at least $250 million par amount outstanding and with at least one year to final maturity. The Lipper Flexible Portfolio Funds Index is an equal-weighted index of the 30 largest mutual funds within the Flexible Portfolio fund classification, as defined by Lipper, and shows how the Fund's performance compares with the returns of an index of funds with similar investment objectives. The 50/50 Blended Benchmark was established by the Investment Manager to show how the Fund's performance compares to an equally weighted custom composite of the Fund's primary equity and primary debt benchmarks, the S&P 500® Index and the Barclays U.S. Aggregate Bond Index, respectively. The percentage of the Fund's assets allocated to underlying stock and bond Portfolio Funds will vary, and accordingly the composition of the Fund's portfolio will not always reflect the composition of the 50/50 Blended Benchmark.
Performance Table Closing [Text Block] rr_PerformanceTableClosingTextBlock

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs). The after-tax returns are shown only for Class Z shares and will vary for other share classes.
(Columbia Thermostat Fund) | S&P 500® Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 16.00%
5 Years rr_AverageAnnualReturnYear05 1.66%
10 Years rr_AverageAnnualReturnYear10 7.10%
(Columbia Thermostat Fund) | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 4.22%
5 Years rr_AverageAnnualReturnYear05 5.95%
10 Years rr_AverageAnnualReturnYear10 5.18%
(Columbia Thermostat Fund) | 50-50 S&P 500/Barclays Aggregate Bond (an equally weighted custom composite of the Fund's primary benchmarks for equity and debt securities, established by the Investment Manager; reflects no deductions for fees, expenses or taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 10.13%
5 Years rr_AverageAnnualReturnYear05 4.26%
10 Years rr_AverageAnnualReturnYear10 6.44%
(Columbia Thermostat Fund) | Lipper Flexible Portfolio Funds Index (reflects no deductions for taxes)
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 13.34%
5 Years rr_AverageAnnualReturnYear05 2.72%
10 Years rr_AverageAnnualReturnYear10 7.31%
(Columbia Thermostat Fund) | Class A Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice 5.75%
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [1]
Management fees rr_ManagementFeesOverAssets 0.10%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other expenses rr_OtherExpensesOverAssets 0.24% [4]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.60%
Total annual Fund operating expenses rr_ExpensesOverAssets 1.19% [6]
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.09%) [9]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.10%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 681
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 923
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,184
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,928
1 Year rr_AverageAnnualReturnYear01 6.84%
5 Years rr_AverageAnnualReturnYear05 3.70%
10 Years rr_AverageAnnualReturnYear10 6.97%
(Columbia Thermostat Fund) | Class B Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 5.00% [2]
Management fees rr_ManagementFeesOverAssets 0.10%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 0.75%
Other expenses rr_OtherExpensesOverAssets 0.34% [4]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.60%
Total annual Fund operating expenses rr_ExpensesOverAssets 1.79% [6]
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.19%) [9]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.60%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 663
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 845
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,152
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,932
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 163
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 545
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 952
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 1,932
1 Year rr_AverageAnnualReturnYear01 7.78%
5 Years rr_AverageAnnualReturnYear05 4.07%
10 Years rr_AverageAnnualReturnYear10 7.03%
(Columbia Thermostat Fund) | Class C Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther 1.00% [3]
Management fees rr_ManagementFeesOverAssets 0.10%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other expenses rr_OtherExpensesOverAssets 0.24% [4]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.60%
Total annual Fund operating expenses rr_ExpensesOverAssets 1.94% [6]
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.09%) [9]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 1.85%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 288
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 600
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,039
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 2,257
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 188
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 600
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 1,039
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 2,257
1 Year rr_AverageAnnualReturnYear01 11.52%
5 Years rr_AverageAnnualReturnYear05 4.16%
10 Years rr_AverageAnnualReturnYear10 6.82%
(Columbia Thermostat Fund) | Class R4 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.10%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.34% [4]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.60%
Total annual Fund operating expenses rr_ExpensesOverAssets 1.04% [6]
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.19%) [9]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 0.85%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 87
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 312
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 556
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,254
1 Year rr_AverageAnnualReturnYear01 13.68%
5 Years rr_AverageAnnualReturnYear05 5.19%
10 Years rr_AverageAnnualReturnYear10 7.89%
(Columbia Thermostat Fund) | Class R5 Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.10%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.19% [4]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.60%
Total annual Fund operating expenses rr_ExpensesOverAssets 0.89% [6]
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.06%) [9]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 0.83%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 85
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 278
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 487
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,091
1 Year rr_AverageAnnualReturnYear01 13.66%
5 Years rr_AverageAnnualReturnYear05 5.19%
10 Years rr_AverageAnnualReturnYear10 7.89%
(Columbia Thermostat Fund) | Class Y Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.10%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.14% [4]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.60%
Total annual Fund operating expenses rr_ExpensesOverAssets 0.84% [6]
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.06%) [9]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 0.78%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 80
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 262
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 460
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,032
1 Year rr_AverageAnnualReturnYear01 13.63%
5 Years rr_AverageAnnualReturnYear05 5.18%
10 Years rr_AverageAnnualReturnYear10 7.89%
(Columbia Thermostat Fund) | Class Z Shares
  
Risk/Return: rr_RiskReturnAbstract  
Maximum sales charge (load) imposed on purchases, as a % of offering price rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or current net asset value rr_MaximumDeferredSalesChargeOverOther none
Management fees rr_ManagementFeesOverAssets 0.10%
Distribution and/or service (Rule 12b-1) fees rr_DistributionAndService12b1FeesOverAssets none
Other expenses rr_OtherExpensesOverAssets 0.21% [4]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.60%
Total annual Fund operating expenses rr_ExpensesOverAssets 0.91% [6]
Fee waivers and/or reimbursements rr_FeeWaiverOrReimbursementOverAssets (0.06%) [9]
Total annual Fund operating expenses after fee waivers and/or reimbursements rr_NetExpensesOverAssets 0.85%
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 87
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 284
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 498
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,114
Annual Return 2003 rr_AnnualReturn2003 19.79%
Annual Return 2004 rr_AnnualReturn2004 9.17%
Annual Return 2005 rr_AnnualReturn2005 5.50%
Annual Return 2006 rr_AnnualReturn2006 10.86%
Annual Return 2007 rr_AnnualReturn2007 8.49%
Annual Return 2008 rr_AnnualReturn2008 (30.53%)
Annual Return 2009 rr_AnnualReturn2009 32.29%
Annual Return 2010 rr_AnnualReturn2010 17.58%
Annual Return 2011 rr_AnnualReturn2011 4.85%
Annual Return 2012 rr_AnnualReturn2012 13.69%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel 2nd quarter 2009:
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 19.33%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel 4th quarter 2008:
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (19.26%)
1 Year rr_AverageAnnualReturnYear01 13.69%
5 Years rr_AverageAnnualReturnYear05 5.19%
10 Years rr_AverageAnnualReturnYear10 7.89%
(Columbia Thermostat Fund) | Class Z Shares | returns after taxes on distributions
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 13.10%
5 Years rr_AverageAnnualReturnYear05 4.66%
10 Years rr_AverageAnnualReturnYear10 6.70%
(Columbia Thermostat Fund) | Class Z Shares | returns after taxes on distributions and sale of Fund shares
  
Risk/Return: rr_RiskReturnAbstract  
1 Year rr_AverageAnnualReturnYear01 9.06%
5 Years rr_AverageAnnualReturnYear05 4.22%
10 Years rr_AverageAnnualReturnYear10 6.33%
[1] Contingent deferred sales charges (CDSC) on certain investments of between $1 million and $50 million redeemed within 18 months of purchase, charged as follows: 1.00% CDSC if redeemed within 12 months of purchase, and 0.50% CDSC if redeemed more than 12, but less than 18, months of purchase, with certain limited exceptions.
[2] This charge decreases over time.
[3] This charge applies to investors who buy Class C shares and redeem them within one year of purchase, with certain limited exceptions.
[4] Other expenses have been restated to reflect contractual changes to certain fees paid by the Fund.
[5] Other expenses for Class A, Class C, Class I, Class R4, Class R5 and Class Z shares have been restated to reflect contractual changes to certain fees paid by the Fund. Other expenses for Class Y shares are based on estimated amounts for the Fund's current fiscal year.
[6] Total annual Fund operating expenses include the annualized average weighted fees and expenses of acquired funds (underlying Portfolio Funds). As a result, the amount shown is higher than the ratio of expenses to average net assets included in Financial Highlights, which reflects only those expenses paid directly by the Fund.
[7] Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any) do not exceed the annual rates of 1.75% for Class A shares, 2.50% for Class C shares, 1.46% for Class I shares, 1.51% for Class R5 shares and 1.50% for Class Z shares, through April 30, 2014. This arrangement may only be modified or amended with approval from all parties to the arrangement, including the Fund and the Investment Manager.
[8] Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any) do not exceed the annual rates of 1.85% for Class A shares, 2.60% for Class C shares, 1.54% for Class I shares, 1.60% for Class R4 shares, 1.59% for Class R5 shares, 1.54% for Class Y shares and 1.60% for Class Z shares, through April 30, 2014. This arrangement may only be modified or amended with approval from all parties to the arrangement, including the Fund and the Investment Manager.
[9] Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in the Portfolio Funds (acquired funds)), do not exceed the annual rates of 0.50% for Class A shares, 1.00% for Class B shares, 1.25% for Class C shares, 0.25% for Class R4 shares, 0.23% for Class R5 shares, 0.18% for Class Y shares and 0.25% for Class Z shares, through April 30, 2014. This arrangement may only be modified or amended with approval from all parties to the arrangement, including the Fund and the Investment Manager.
[10] Year-to-date return as of March 31, 2013: 9.82%
[11] Year-to-date return as of March 31, 2013: 4.25%
[12] Year-to-date return as of March 31, 2013: 3.40%
[13] Year-to-date return as of March 31, 2013: 7.03%
[14] Year-to-date return as of March 31, 2013: 3.13%
[15] Year-to-date return as of March 31, 2013: 10.64%
[16] Year-to-date return as of March 31, 2013: 10.46%
[17] Year-to-date return as of March 31, 2013: 4.10%