v2.4.0.6

Covered Assets and FDIC Loss-sharing Asset (FDIC Loss-sharing Asset) (Details) (FDIC Loss-sharing Asset [Member], USD $) In Thousands, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2011 | Dec. 31, 2010
FDIC Loss-sharing Asset [Member] |  |
Covered Assets And FDIC Loss Sharing Asset [Line Items] |  |
Balance at beginning of period | $ 205,991 | $ 0
Established through acquisitions | 68,734 | 210,405
Cash received from the FDIC | (54,200) | (11,198)
FDIC reimbursable losses, net | 4,042 | 1,876
Amortization, net | (46,049) | 1,139
Impairment | (1,318) | 4,844
Sale of other real estate | (4,346) | (1,148)
Other | 2,217 | 73
Balance at end of period | $ 175,071 | $ 205,991

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- Details
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Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition FDIC Loss-sharing Asset + References No definition available. + Details
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- Definition FDIC Loss-sharing Asset, Acquisitions + References No definition available. + Details
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- Definition FDIC Loss-sharing Asset, Amortization, Net + References No definition available. + Details
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X
- Definition FDIC Loss-sharing Asset, Cash Payments Received + References No definition available. + Details
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- Definition FDIC Loss-sharing Asset, Disposals + References No definition available. + Details
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- Definition FDIC Loss-sharing Asset, Net Reimbursable Losses + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
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- Definition FDIC Loss-sharing Asset, Net Write Offs + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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- Definition FDIC Loss-sharing Asset, Other + References No definition available. + Details
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Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration