XML 76 R63.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Commitments to Extend Credit [Member] |  |
Other Commitments [Line Items] |  |
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability | $ 2,460,000 | $ 2,620,000
Standby Letters of Credit [Member] |  |
Other Commitments [Line Items] |  |
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability | 42,500 | 51,300
Commercial Letter of Credit and other off-balance sheet liabilities [Member] |  |
Other Commitments [Line Items] |  |
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability | $ 113 | $ 159

X
- Definition The fair value of financial liabilities, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611 + Details
Name: | us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_OtherCommitmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommitmentsToExtendCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=colb_CommercialLetterofCreditandotheroffbalancesheetliabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |