XML 57 R47.htm IDEA: XBRL DOCUMENT
v3.21.2

Loans Receivable, Net - Narrative (Details) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 USD ($) Loan | Sep. 30, 2020 USD ($) Loan | Sep. 30, 2021 USD ($) Loan | Sep. 30, 2020 USD ($) Loan | Dec. 31, 2020 USD ($)
Loans and Leases Receivable Disclosure |  |  |  |  |
Interest reversed on non-accrual loans |  |  | $ 472 | $ 628 |
Number of loans | Loan | 0 | 6 | 10 | 16 |
TDR with pre modification loan balance for which OREO was received | $ 1,624 | $ 2,265 | $ 1,624 | $ 2,265 |
Consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process | 83 |  | 83 |  | $ 548
OREO secured by residential real estate | $ 88 |  | $ 88 |  | $ 273

X
- Definition Amount of interest income reversed on financing receivable that went on nonaccrual status during the period. + References No definition available. + Details
Name: | gbci_FinancingReceivableNonaccrualInterestIncomeReversed
Namespace Prefix: | gbci_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Real Estate Acquired Through Foreclosure, Secured by Residential Real Estate + References No definition available. + Details
Name: | gbci_RealEstateAcquiredThroughForeclosureSecuredbyResidentialRealEstate
Namespace Prefix: | gbci_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition TDR with pre modification loan balance, for which OREO was received. + References No definition available. + Details
Name: | gbci_TDRWithPreModificationLoanBalanceForWhichOreoWasReceived
Namespace Prefix: | gbci_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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=123577603&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LoansAndLeasesReceivableDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
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=123577603&loc=SL49126937-111524 + Details
Name: | us-gaap_MortgageLoansInProcessOfForeclosureAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant