XML 65 R55.htm IDEA: XBRL DOCUMENT
v3.20.2

Other Real Estate Owned (Summary of Other Real Estate Owned) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Other Real Estate Owned [Line Items] |  |  |  |
Balance, beginning of period | $ 747 | $ 1,118 | $ 552 | $ 6,019
Transfers in | 475 | 0 | 1,033 | 386
Valuation adjustments | 0 | 0 | 0 | (195)
Proceeds from Sale of OREO Property | 681 | 588 | 1,026 | 6,382
Gain on sale of OREO, net | 82 | 95 | 64 | 797
Total OREO, end of period | 623 | $ 625 | 623 | $ 625
Mortgage Loans in Process of Foreclosure, Amount | 436 |  | 436 |
One-to-Four Family Residential [Member] |  |  |  |
Other Real Estate Owned [Line Items] |  |  |  |
Total OREO, end of period | $ 0 |  | $ 0 |

X
- Definition Other Real Estate Owned [Line Items] + References No definition available. + Details
Name: | colb_OtherRealEstateOwnedLineItems
Namespace Prefix: | colb_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Real Estate Acquired Through Foreclosure Transfers In Net Of Write Downs + References No definition available. + Details
Name: | colb_RealEstateAcquiredThroughForeclosureTransfersInNetOfWriteDowns
Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Transfer Other Real Estate Write Down + References No definition available. + Details
Name: | colb_TransferOtherRealEstateWriteDown
Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net gain (loss) resulting from sales and other disposals of other real estate owned, increases (decreases) in the valuation allowance for foreclosed real estate, and write-downs of other real estate owned after acquisition or physical possession. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.14(d)) -URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260 + Details
Name: | us-gaap_GainsLossesOnSalesOfOtherRealEstate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 35 -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL49126937-111524 + Details
Name: | us-gaap_MortgageLoansInProcessOfForeclosureAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cash inflow from proceeds From Sales of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5162-111524 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=121593590&loc=d3e4437-111522 + Details
Name: | us-gaap_RealEstateAcquiredThroughForeclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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