XML 73 R60.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Summary of Significant Accounting Policies (Details) | 12 Months Ended
--- | ---
Dec. 31, 2021 USD ($) location
Accounting Policies [Line Items] |
Number Of Branch Locations | 153
Number Of Days Used To Determine Treatment As Cash Equivalent | 90 days
FHLB membership stock purchase requirement cap | $ | $ 10,000,000
Federal Home Loan Bank stock, par value | $ | $ 100
Number of Days of Delinquency at Which Loans Are Categorized As Non Accrual Status | 90 days
WASHINGTON |
Accounting Policies [Line Items] |
Number Of Branch Locations | 68
OREGON |
Accounting Policies [Line Items] |
Number Of Branch Locations | 59
IDAHO |
Accounting Policies [Line Items] |
Number Of Branch Locations | 15
CALIFORNIA |
Accounting Policies [Line Items] |
Number Of Branch Locations | 11
Vehicles |
Accounting Policies [Line Items] |
Property, Plant and Equipment, Estimated Useful Lives | 5
Minimum | Building and Building Improvements [Member] |
Accounting Policies [Line Items] |
Property, Plant and Equipment, Estimated Useful Lives | 5
Minimum | Furniture and Fixtures |
Accounting Policies [Line Items] |
Property, Plant and Equipment, Estimated Useful Lives | 3
Minimum | Software |
Accounting Policies [Line Items] |
Property, Plant and Equipment, Estimated Useful Lives | 3
Maximum | Building and Building Improvements [Member] |
Accounting Policies [Line Items] |
Property, Plant and Equipment, Estimated Useful Lives | 39
Maximum | Furniture and Fixtures |
Accounting Policies [Line Items] |
Property, Plant and Equipment, Estimated Useful Lives | 7
Maximum | Software |
Accounting Policies [Line Items] |
Property, Plant and Equipment, Estimated Useful Lives | 5
Designated as Hedging Instrument | Interest rate collar |
Accounting Policies [Line Items] |
Derivative, Notional Amount | $ | $ 500,000,000

X
- Definition Accounting Policies [Line Items] + References No definition available. + Details
Name: | colb_AccountingPoliciesLineItems
Namespace Prefix: | colb_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition FHLB membership stock purchase requirement cap + References No definition available. + Details
Name: | colb_FHLBmembershipstockpurchaserequirementcap
Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Federal Home Loan Bank stock, par value + References No definition available. + Details
Name: | colb_FederalHomeLoanBankstockparvalue
Namespace Prefix: | colb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number Of Branch Locations + References No definition available. + Details
Name: | colb_NumberOfBranchLocations
Namespace Prefix: | colb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of Days Used To Determine Treatment As Cash Equivalent + References No definition available. + Details
Name: | colb_NumberOfDaysUsedToDetermineTreatmentAsCashEquivalent
Namespace Prefix: | colb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Days of Delinquency at Which Loans Are Categorized As Non Accrual Status + References No definition available. + Details
Name: | colb_NumberofDaysofDelinquencyatWhichLoansAreCategorizedAsNonAccrualStatus
Namespace Prefix: | colb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Describes the periods of time over which an entity anticipates to receive utility from its property, plant and equipment (that is, the periods of time over which an entity allocates the initial cost of its property, plant and equipment). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 35 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=123364984&loc=d3e1205-110223 + Details
Name: | us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_StatementGeographicalAxis=stpr_WA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=stpr_OR
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=stpr_ID
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=stpr_CA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_VehiclesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingAndBuildingImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ComputerSoftwareIntangibleAssetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=colb_InterestratecollarDomain
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |