XML 64 R50.htm IDEA: XBRL DOCUMENT
v3.19.2

Loans Loans (Analysis of Troubled Debt Restructurings) (Details) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2019 USD ($) Modifications contract | Jun. 30, 2018 USD ($) Modifications contract | Jun. 30, 2019 USD ($) Modifications contract | Jun. 30, 2018 USD ($) Modifications contract | Dec. 31, 2018 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | contract | 0 | 0 | 1 | 0 |
Financing Receivable Modifications Additional Commitment To Lend | $ 464 |  | $ 464 |  | $ 2,100
Financing Receivable, Troubled Debt Restructuring, Subsequent Default | $ 0 | $ 0 | $ 26 | $ 0 |
Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications | 7 | 15 | 10 | 24 |
Financing Receivable, Troubled Debt Restructuring, Premodification | $ 1,036 | $ 3,918 | $ 1,869 | $ 6,402 |
Financing Receivable, Troubled Debt Restructuring, Postmodification | $ 1,036 | $ 3,918 | $ 1,869 | $ 6,402 |
Loans, Excluding Purchased Credit Impaired Loans [Member] | Secured Loans [Member] |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications | 3 | 7 | 5 | 8 |
Financing Receivable, Troubled Debt Restructuring, Premodification | $ 918 | $ 2,644 | $ 1,534 | $ 3,094 |
Financing Receivable, Troubled Debt Restructuring, Postmodification | $ 918 | $ 2,644 | $ 1,534 | $ 3,094 |
Loans, Excluding Purchased Credit Impaired Loans [Member] | Income Property Multifamily [Member] |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications |  |  | 1 | 1 |
Financing Receivable, Troubled Debt Restructuring, Premodification |  |  | $ 217 | $ 891 |
Financing Receivable, Troubled Debt Restructuring, Postmodification |  |  | $ 217 | $ 891 |
Loans, Excluding Purchased Credit Impaired Loans [Member] | Consumer Portfolio Segment [Member] |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications | 4 | 8 | 4 | 15 |
Financing Receivable, Troubled Debt Restructuring, Premodification | $ 118 | $ 1,274 | $ 118 | $ 2,417 |
Financing Receivable, Troubled Debt Restructuring, Postmodification | $ 118 | $ 1,274 | $ 118 | $ 2,417 |

X
- Definition Financing Receivable Modifications Additional Commitment To Lend + References No definition available. + Details
Name: | colb_FinancingReceivableModificationsAdditionalCommitmentToLend
Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_FinancingReceivableModificationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of financing receivables that have been modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after troubled debt restructuring, of modified financing receivable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, before troubled debt restructuring, of financing receivable to be modified. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953682-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953682-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | colb_LoansByMajorCategoryAxis=colb_LoansExcludingPurchasedCreditImpairedLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=colb_SecuredLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=colb_IncomePropertyMultifamilyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |