XML 69 R40.htm IDEA: XBRL DOCUMENT
v3.23.1

Business Combinations and Asset Acquisitions - Pro Forma (Details) - Umpqua Bank and Columbia Banking System Merger - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2023 | Mar. 31, 2022
Asset Acquisition [Line Items] |  |
Business acquisition, pro forma net interest income | $ 526,260 | $ 470,055
Business Acquisition, Pro Forma Non-interest Income | 88,572 | 102,224
Business Acquisition, Pro Forma Net Income (Loss) | 217,135 | $ 22,672
Business Combination, Acquisition Related Costs - Combined for proforma | $ 143,900 |

X
- Definition Business acquisition, pro forma net interest income + References No definition available. + Details
Name: | colb_BusinessAcquisitionProFormaNetInterestIncome
Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Business Acquisition, Pro Forma Non-interest Income + References No definition available. + Details
Name: | colb_BusinessAcquisitionProFormaNonInterestIncome
Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Business Combination, Acquisition Related Costs - Combined for proforma + References No definition available. + Details
Name: | colb_BusinessCombinationAcquisitionRelatedCostsCombinedForProforma
Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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_AssetAcquisitionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(3) -URI https://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(2) -URI https://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
Name: | us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=colb_UmpquaBankAndColumbiaBankingSystemMergerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |