Risk/Return:

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dei_DocumentPeriodEndDate

May 31, 2011

Central Index Key

dei_EntityCentralIndexKey

0000773757

Document Creation Date

dei_DocumentCreationDate

Jun. 18, 2012

Prospectus Date

rr_ProspectusDate

Jun. 18, 2012

Risk/Return:

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Strategy Narrative [Text Block]

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Under normal circumstances, the Fund will invest at least 80% of its net assets in fixed-income securities of foreign issuers. Generally, the Fund seeks to achieve its investment objective by investing in debt securities of issuers in at least three foreign countries, including foreign governments, quasi-governments, provincials, agencies, instrumentalities, supranationals and corporate entities.

The Fund is not limited as to any particular countries in which it may invest. The Fund will invest in the securities of issuers in developed countries and the securities of issuers in emerging or developing countries. Securities may be denominated in foreign currencies, baskets of foreign currencies or the U.S. dollar. The average portfolio duration will vary, based on the forecast for interest rates by Columbia Management Investment Advisers, LLC, the Fund's investment adviser (the Investment Manager).

Under normal market conditions, at least 80% of the Fund's net assets (including the amount of any borrowings for investment purposes) will be invested in investment-grade government or corporate debt obligations, including money market instruments, of issuers located in at least three foreign countries. Although the Fund emphasizes high- and medium-quality debt securities, it may assume some credit risk in seeking to achieve higher dividends and/or capital appreciation by investing in below investment-grade fixed-income securities (junk bonds).

The Fund may invest in derivatives, including futures, forwards, options, swap contracts and other derivative instruments. The Fund may invest in derivatives for both hedging and non-hedging purposes, including, for example, to seek to enhance returns or as a substitute for a position in an underlying asset. The Fund may attempt to hedge the effects of currency value fluctuations on the Fund's investments. The Fund also may invest in private placements.

In addition, the Investment Manager may use futures (including index and currency futures) in an effort to produce incremental earnings, to hedge existing positions, to increase market or credit exposure, or to increase investment flexibility (including using the derivative as a substitute for the purchase or sale of an underlying security, currency, commodity or other instrument).

The Fund is non-diversified, which means that it can invest a greater percentage of its assets in a single issuer than can a diversified fund.

The Investment Manager evaluates a number of factors in identifying investment opportunities and constructing the Fund's portfolio. The Investment Manager considers local, national and global economic conditions, market conditions, interest rate movements and other relevant factors to determine the allocation of the Fund's assets among different issuers, industry sectors and maturities.

The Investment Manager, in connection with selecting individual investments for the Fund, evaluates a security based on its potential to generate income and/or capital appreciation. The Investment Manager considers, among other factors, the creditworthiness of the issuer of the security and the various features of the security, such as its interest rate, yield, maturity, any call features and value relative to other securities.

The Investment Manager may sell a security if the Investment Manager believes that there is deterioration in the issuer's financial circumstances, or that other investments are more attractive; if there is deterioration in a security's credit rating; or for other reasons.

Performance Narrative [Text Block]

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The table compares the Fund's returns for each period with those of the Fund's primary benchmark, the Citigroup Non-U.S. Dollar World Government Bond (All Maturities) Index (the Citigroup Non-U.S. WGBI or the Primary Benchmark). The Citigroup Non-U.S. WGBI is calculated on a market-weighted basis and includes investment-grade, fixed-rate bonds, issued by governments outside of the United States, with a remaining maturity of one year or longer and with amounts outstanding of at least the equivalent of U.S. $25 million. The index excludes floating or variable rate bonds, securities aimed principally at non-institutional investors and private placement-type securities. As of the date of this supplement, the Citigroup Non-U.S. WGBI includes government bonds from 21 countries. The number of countries will fluctuate depending on whether a country is meeting the inclusion criteria — market size, credit and lack of barriers-to-entry. Barriers-to-entry include, but are not limited to, government discouragement of foreign investor participation.

The table also compares the Fund's returns to a secondary benchmark, which is a weighted custom composite, established by the Investment Manager (the Blended Benchmark). The Blended Benchmark consists of a 60% weighting in the Citigroup World Government Bond (excluding the U.S. and Japan) Index (the Citigroup WGBI — ex U.S./Japan), a 20% weighting in the Citigroup Japan Government Bond Index (the Citigroup Japan GBI) and a 20% weighting in the JPMorgan Government Bond Index — Emerging Markets Global Diversified Composite (the JPM GBI EM — Global Diversified). The Citigroup WGBI — ex U.S./Japan has the same calculation and inclusion criteria as the Primary Benchmark, while excluding issues from the United States and also Japan. The Citigroup Japan GBI is a market-weighted index based on Yen-denominated debt instruments issued by the government of Japan. The JPM GBI — EM Global Diversified tracks total returns for emerging markets local-currency-denominated fixed income instruments.

The Primary Benchmark and the components of the Blended Benchmark are each "unhedged" against non-U.S. dollar denominated currency fluctuation. The Fund added the Blended Benchmark as a secondary benchmark, effective July 1, 2012, because it is representative of the Fund's investment approach.

1 Year

rr_AverageAnnualReturnYear01

5.17%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 01, 2008

Risk/Return:

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Life of Fund

rr_AverageAnnualReturnSinceInception

8.49%