XML 59 R49.htm IDEA: XBRL DOCUMENT
v3.20.2

Loans Loans (Analysis of Troubled Debt Restructurings) (Details) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 USD ($) Modifications | Sep. 30, 2019 USD ($) Modifications | Sep. 30, 2020 USD ($) Modifications | Sep. 30, 2019 USD ($) Modifications
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications | 9 | 11 | 18 | 21
Financing Receivable, Troubled Debt Restructuring, Premodification | $ 4,013 | $ 5,384 | $ 7,066 | $ 7,253
Financing Receivable, Troubled Debt Restructuring, Postmodification | $ 4,013 | $ 5,384 | $ 7,066 | $ 7,253
Commercial Business [Member] |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications | 4 | 5 | 10 | 10
Financing Receivable, Troubled Debt Restructuring, Premodification | $ 795 | $ 5,026 | $ 2,757 | $ 6,560
Financing Receivable, Troubled Debt Restructuring, Postmodification | $ 795 | $ 5,026 | $ 2,757 | $ 6,560
Agriculture [Member] |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications | 1 | 0 | 2 | 0
Financing Receivable, Troubled Debt Restructuring, Premodification | $ 2,600 | $ 0 | $ 3,495 | $ 0
Financing Receivable, Troubled Debt Restructuring, Postmodification | $ 2,600 | $ 0 | $ 3,495 | $ 0
One-to-Four Family Residential [Member] |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications | 4 | 5 | 6 | 10
Financing Receivable, Troubled Debt Restructuring, Premodification | $ 618 | $ 357 | $ 814 | $ 692
Financing Receivable, Troubled Debt Restructuring, Postmodification | $ 618 | $ 357 | $ 814 | $ 692
Consumer Loan [Member] |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Financing Receivable, Modifications, Number of Contracts | Modifications | 0 | 1 | 0 | 1
Financing Receivable, Troubled Debt Restructuring, Premodification | $ 0 | $ 1 | $ 0 | $ 1
Financing Receivable, Troubled Debt Restructuring, Postmodification | $ 0 | $ 1 | $ 0 | $ 1

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=121611835&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=121611835&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=121611835&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

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

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

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