$GBCI
GLACIER BANCORP, INC. Stock $gbci

$gbci Overview Financials Valuation SEC Filings Company Website

2024 Q1 Form 10-K Financial Statement

#000086867124000042 Filed on February 23, 2024

Income Statement

Concept	2024 Q1	2023 Q4	2023
Revenue	$22.15M	$273.5M	$88.55M
YoY Change	6.09%	21.51%	6.88%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$9.852M	$9.543M	$37.14M
YoY Change	6.38%	0.01%	1.8%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$112.9M	$107.0M	$326.0M
YoY Change	147.12%	409.08%	690.03%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$36.38M	$62.11M	$267.6M
YoY Change	-50.6%	-36.26%	-27.73%
Income Tax	$3.750M	$7.796M	$44.68M
% Of Pretax Income	10.31%	12.55%	16.7%
Net Earnings	$32.63M	$54.32M	$222.9M
YoY Change	-46.7%	-31.83%	-26.48%
Net Earnings / Revenue	147.29%	19.86%	251.76%
Basic Earnings Per Share	$0.29	$0.49	$2.01
Diluted Earnings Per Share	$0.29	$0.49	$2.01
COMMON SHARES
Basic Shares Outstanding	113.4M shares	110.9M shares	110.9M shares
Diluted Shares Outstanding	112.6M shares		110.9M shares

Balance Sheet

Concept	2024 Q1	2023 Q4	2023
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$788.7M	$1.354B
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$443.3M	$421.8M	$421.8M
YoY Change	10.89%	5.95%	5.95%
Goodwill	$1.024B	$985.4M
YoY Change	3.89%	0.0%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$161.3M	$159.1M	$159.1M
YoY Change	-6.45%	-17.66%	-17.66%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$27.82B	$27.74B	$27.74B
YoY Change	0.07%	4.16%	4.16%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$32.58M	$125.9M	$125.9M
YoY Change	263.34%	2807.11%	2807.11%
Accrued Expenses	$43.71M	$44.32M	$44.32M
YoY Change	-5.34%	-4.85%	-4.85%
Deferred Revenue
YoY Change
Short-Term Debt	$1.540B	$4.227B	$4.227B
YoY Change	29.27%	346.85%	346.85%
Long-Term Debt Due	$3.911M	$3.847M	$3.847M
YoY Change	9.43%	-3.51%	-3.51%
Total Short-Term Liabilities	$1.573B	$4.353B	$4.353B
YoY Change	31.02%	100402.36%	100402.36%
LONG-TERM LIABILITIES
Long-Term Debt	$221.8M	$214.6M	$214.6M
YoY Change	-92.48%	2.17%	2.17%
Other Long-Term Liabilities	$349.4M	$225.8M	$225.8M
YoY Change	43.83%	0.26%	0.26%
Total Long-Term Liabilities	$571.2M	$440.4M	$440.4M
YoY Change	-82.11%	1.18%	1.18%
TOTAL LIABILITIES
Total Short-Term Liabilities	$1.573B	$4.353B	$4.353B
Total Long-Term Liabilities	$571.2M	$440.4M	$440.4M
Total Liabilities	$24.71B	$24.72B	$24.72B
YoY Change	-0.66%	3.91%	3.91%
SHAREHOLDERS EQUITY
Retained Earnings	$1.038B	$1.043B
YoY Change	4.72%	7.88%
Common Stock	$2.444B	$2.350B
YoY Change	4.23%	0.26%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$3.111B	$3.020B	$3.020B
YoY Change
Total Liabilities & Shareholders Equity	$27.82B	$27.74B	$27.74B
YoY Change	0.07%	4.16%	4.16%

Cashflow Statement

Concept	2024 Q1	2023 Q4	2023
OPERATING ACTIVITIES
Net Income	$32.63M	$54.32M	$222.9M
YoY Change	-46.7%	-31.83%	-26.48%
Depreciation, Depletion And Amortization	$9.852M	$9.543M	$37.14M
YoY Change	6.38%	0.01%	1.8%
Cash From Operating Activities	-$56.73M	$151.2M	$500.7M
YoY Change	-157.78%	26.1%	6.39%
INVESTING ACTIVITIES
Capital Expenditures	$4.290M	$12.78M	$49.28M
YoY Change	-47.43%	101.98%	112.08%
Acquisitions			$0.00
YoY Change
Other Investing Activities	$213.7M	$88.19M	-$158.2M
YoY Change	-1084.37%	54.74%	-88.09%
Cash From Investing Activities	$209.4M	$75.41M	-$207.5M
YoY Change	-801.02%	48.84%	-84.65%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-$718.3M	-544.4M	$659.1M
YoY Change	-167.82%	180.91%	-22.04%
NET CHANGE
Cash From Operating Activities	-$56.73M	151.2M	$500.7M
Cash From Investing Activities	$209.4M	75.41M	-$207.5M
Cash From Financing Activities	-$718.3M	-544.4M	$659.1M
Net Change In Cash	-$565.7M	-317.8M	$952.3M
YoY Change	-150.17%	1268.62%	-2768.31%
FREE CASH FLOW
Cash From Operating Activities	-$56.73M	$151.2M	$500.7M
Capital Expenditures	$4.290M	$12.78M	$49.28M
Free Cash Flow	-$61.02M	$138.4M	$451.4M
YoY Change	-167.79%	21.88%	0.9%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2023Q4	us-gaap	Goodwill Goodwill	985393000	usd
CY2022	us-gaap	Servicing Asset At Amortized Value Amortization1 ServicingAssetAtAmortizedValueAmortization1	1812000	usd
CY2021	us-gaap	Servicing Asset At Amortized Value Amortization1 ServicingAssetAtAmortizedValueAmortization1	1926000	usd
CY2023Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	12534000	usd
CY2022Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	13488000	usd
CY2023Q4	us-gaap	Servicing Asset ServicingAsset	1570834000	usd
CY2023	dei	Entity Central Index Key EntityCentralIndexKey	0000868671
CY2023	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2023
CY2023	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2023	dei	Amendment Flag AmendmentFlag	false
CY2023	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	operatingsegment
CY2023	us-gaap	Number Of Reporting Units NumberOfReportingUnits	1	reporting_unit
CY2022Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss Statement Of Financial Position Extensible List FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#InterestReceivable
CY2023Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss Statement Of Financial Position Extensible List FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#InterestReceivable
CY2022Q4	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.glacierbancorp.com/20231231#PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
CY2023Q4	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.glacierbancorp.com/20231231#PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.glacierbancorp.com/20231231#PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.glacierbancorp.com/20231231#PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
CY2023Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherLiabilities
CY2022Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherLiabilities
CY2022Q4	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherBorrowings
CY2023Q4	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2023#OtherBorrowings
CY2023Q4	us-gaap	Hedged Asset Statement Of Financial Position Extensible Enumeration HedgedAssetStatementOfFinancialPositionExtensibleEnumeration	http://fasb.org/us-gaap/2023#DebtSecuritiesAvailableForSaleExcludingAccruedInterest
CY2023	dei	Document Annual Report DocumentAnnualReport	true
CY2023	dei	Document Period End Date DocumentPeriodEndDate	2023-12-31
CY2023	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2023	dei	Document Transition Report DocumentTransitionReport	false
CY2023	dei	Entity File Number EntityFileNumber	000-18911
CY2023	dei	Entity Registrant Name EntityRegistrantName	GLACIER BANCORP, INC.
CY2023	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	MT
CY2023	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	81-0519541
CY2023	dei	Entity Address Address Line1 EntityAddressAddressLine1	49 Commons Loop
CY2023	dei	Entity Address City Or Town EntityAddressCityOrTown	Kalispell,
CY2023	dei	Entity Address State Or Province EntityAddressStateOrProvince	MT
CY2023	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	59901
CY2023	dei	City Area Code CityAreaCode	(406)
CY2023	dei	Local Phone Number LocalPhoneNumber	756-4200
CY2023	dei	Security12b Title Security12bTitle	Common Stock, $0.01 par value
CY2023	dei	Trading Symbol TradingSymbol	GBCI
CY2023	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2023	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2023	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2023	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2023	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2023	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2023	dei	Entity Small Business EntitySmallBusiness	false
CY2023	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2023	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2023	dei	Document Fin Stmt Error Correction Flag DocumentFinStmtErrorCorrectionFlag	false
CY2023	dei	Entity Shell Company EntityShellCompany	false
CY2023Q2	dei	Entity Public Float EntityPublicFloat	3437780226	usd
CY2024Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	113368242	shares
CY2023	dei	Auditor Name AuditorName	FORVIS, LLP
CY2023	dei	Auditor Location AuditorLocation	Denver, Colorado
CY2023Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	246525000	usd
CY2022Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	300194000	usd
CY2023Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	1107817000	usd
CY2022Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	101801000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents And Federal Funds Sold CashCashEquivalentsAndFederalFundsSold	1354342000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents And Federal Funds Sold CashCashEquivalentsAndFederalFundsSold	401995000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	4785719000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	5307307000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	3502411000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	3715052000	usd
CY2023Q4	us-gaap	Debt Securities DebtSecurities	8288130000	usd
CY2022Q4	us-gaap	Debt Securities DebtSecurities	9022359000	usd
CY2023Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	15691000	usd
CY2022Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	12314000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	16198082000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	15246812000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	192757000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	182283000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	16005325000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	15064529000	usd
CY2023Q4	gbci	Property Plant And Equipment And Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	421791000	usd
CY2022Q4	gbci	Property Plant And Equipment And Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	398100000	usd
CY2023Q4	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	1503000	usd
CY2022Q4	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	32000	usd
CY2023Q4	us-gaap	Interest Receivable InterestReceivable	94526000	usd
CY2022Q4	us-gaap	Interest Receivable InterestReceivable	83538000	usd
CY2023Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	159070000	usd
CY2022Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	193187000	usd
CY2023Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	31870000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	41601000	usd
CY2023Q4	us-gaap	Goodwill Goodwill	985393000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	985393000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	12755000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	82015000	usd
CY2023Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	171101000	usd
CY2022Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	169068000	usd
CY2023Q4	us-gaap	Other Assets OtherAssets	201132000	usd
CY2022Q4	us-gaap	Other Assets OtherAssets	181244000	usd
CY2023Q4	us-gaap	Assets Assets	27742629000	usd
CY2022Q4	us-gaap	Assets Assets	26635375000	usd
CY2023Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	6022980000	usd
CY2022Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	7690751000	usd
CY2023Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	13906187000	usd
CY2022Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	12915804000	usd
CY2023Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	1486850000	usd
CY2022Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	945916000	usd
CY2023Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	0	usd
CY2022Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	1800000000	usd
CY2023Q4	us-gaap	Short Term Non Bank Loans And Notes Payable ShortTermNonBankLoansAndNotesPayable	2740000000	usd
CY2022Q4	us-gaap	Short Term Non Bank Loans And Notes Payable ShortTermNonBankLoansAndNotesPayable	0	usd
CY2023Q4	us-gaap	Other Borrowings OtherBorrowings	81695000	usd
CY2022Q4	us-gaap	Other Borrowings OtherBorrowings	77293000	usd
CY2023Q4	us-gaap	Subordinated Debt SubordinatedDebt	132943000	usd
CY2022Q4	us-gaap	Subordinated Debt SubordinatedDebt	132782000	usd
CY2023Q4	us-gaap	Interest Payable Current And Noncurrent InterestPayableCurrentAndNoncurrent	125907000	usd
CY2022Q4	us-gaap	Interest Payable Current And Noncurrent InterestPayableCurrentAndNoncurrent	4331000	usd
CY2023Q4	us-gaap	Other Liabilities OtherLiabilities	225786000	usd
CY2022Q4	us-gaap	Other Liabilities OtherLiabilities	225193000	usd
CY2023Q4	us-gaap	Liabilities Liabilities	24722348000	usd
CY2022Q4	us-gaap	Liabilities Liabilities	23792070000	usd
CY2023Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies	0	usd
CY2022Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies	0	usd
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CY2022Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	1000000	shares
CY2023Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	1000000	shares
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CY2022Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	234000000	shares
CY2023Q4	us-gaap	Common Stock Value Outstanding CommonStockValueOutstanding	1109000	usd
CY2022Q4	us-gaap	Common Stock Value Outstanding CommonStockValueOutstanding	1108000	usd
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CY2023Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1043181000	usd
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CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-374113000	usd
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CY2023Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	27742629000	usd
CY2022Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	26635375000	usd
CY2023Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	110888942	shares
CY2023Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	110888942	shares
CY2022Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	110777780	shares
CY2022Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	110777780	shares
CY2023	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	201930000	usd
CY2022	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	169035000	usd
CY2021	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	122099000	usd
CY2023	us-gaap	Interest And Fee Income Loans Consumer Real Estate InterestAndFeeIncomeLoansConsumerRealEstate	71328000	usd
CY2022	us-gaap	Interest And Fee Income Loans Consumer Real Estate InterestAndFeeIncomeLoansConsumerRealEstate	57243000	usd
CY2021	us-gaap	Interest And Fee Income Loans Consumer Real Estate InterestAndFeeIncomeLoansConsumerRealEstate	43300000	usd
CY2023	us-gaap	Interest And Fee Income Loans Commercial InterestAndFeeIncomeLoansCommercial	669663000	usd
CY2022	us-gaap	Interest And Fee Income Loans Commercial InterestAndFeeIncomeLoansCommercial	548969000	usd
CY2021	us-gaap	Interest And Fee Income Loans Commercial InterestAndFeeIncomeLoansCommercial	471061000	usd
CY2023	us-gaap	Interest And Fee Income Loans Other Consumer InterestAndFeeIncomeLoansOtherConsumer	74734000	usd
CY2022	us-gaap	Interest And Fee Income Loans Other Consumer InterestAndFeeIncomeLoansOtherConsumer	54393000	usd
CY2021	us-gaap	Interest And Fee Income Loans Other Consumer InterestAndFeeIncomeLoansOtherConsumer	44614000	usd
CY2023	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1017655000	usd
CY2022	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	829640000	usd
CY2021	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	681074000	usd
CY2022	us-gaap	Interest Expense Deposits InterestExpenseDeposits	14526000	usd
CY2021	us-gaap	Interest Expense Deposits InterestExpenseDeposits	12135000	usd
CY2021	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	2303000	usd
CY2023	us-gaap	Interest Expense Other InterestExpenseOther	1056000	usd
CY2023	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	5779000	usd
CY2022	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	4889000	usd
CY2023	us-gaap	Interest Expense InterestExpense	325973000	usd
CY2022	us-gaap	Interest Expense InterestExpense	41261000	usd
CY2021	us-gaap	Interest Expense InterestExpense	18558000	usd
CY2023	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	691682000	usd
CY2022	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	788379000	usd
CY2021	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	662516000	usd
CY2023	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	14795000	usd
CY2022	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	19963000	usd
CY2021	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	23076000	usd
CY2023	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	676887000	usd
CY2022	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	768416000	usd
CY2021	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	639440000	usd
CY2023	gbci	Service Charges And Other Fees ServiceChargesAndOtherFees	75157000	usd
CY2022	gbci	Service Charges And Other Fees ServiceChargesAndOtherFees	72124000	usd
CY2021	gbci	Service Charges And Other Fees ServiceChargesAndOtherFees	59317000	usd
CY2023	gbci	Miscellaneous Loan Fees And Charges MiscellaneousLoanFeesAndCharges	16935000	usd
CY2022	gbci	Miscellaneous Loan Fees And Charges MiscellaneousLoanFeesAndCharges	15350000	usd
CY2021	gbci	Miscellaneous Loan Fees And Charges MiscellaneousLoanFeesAndCharges	12038000	usd
CY2023	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	12202000	usd
CY2022	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	20032000	usd
CY2021	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	63063000	usd
CY2023	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	1510000	usd
CY2022	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	620000	usd
CY2021	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	-638000	usd
CY2023	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	12275000	usd
CY2022	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	12606000	usd
CY2021	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	11040000	usd
CY2023	us-gaap	Noninterest Income NoninterestIncome	118079000	usd
CY2022	us-gaap	Noninterest Income NoninterestIncome	120732000	usd
CY2021	us-gaap	Noninterest Income NoninterestIncome	144820000	usd
CY2023	us-gaap	Labor And Related Expense LaborAndRelatedExpense	309048000	usd
CY2022	us-gaap	Labor And Related Expense LaborAndRelatedExpense	319303000	usd
CY2021	us-gaap	Labor And Related Expense LaborAndRelatedExpense	270644000	usd
CY2023	us-gaap	Occupancy Net OccupancyNet	43578000	usd
CY2022	us-gaap	Occupancy Net OccupancyNet	43261000	usd
CY2021	us-gaap	Occupancy Net OccupancyNet	39394000	usd
CY2023	us-gaap	Advertising Expense AdvertisingExpense	15430000	usd
CY2022	us-gaap	Advertising Expense AdvertisingExpense	14324000	usd
CY2021	us-gaap	Advertising Expense AdvertisingExpense	11949000	usd
CY2023	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	33752000	usd
CY2022	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	30823000	usd
CY2021	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	23470000	usd
CY2023	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	119000	usd
CY2022	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	77000	usd
CY2021	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	236000	usd
CY2023	gbci	General Insurance And Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceAndFederalDepositInsuranceCorporationPremiumExpense	28712000	usd
CY2022	gbci	General Insurance And Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceAndFederalDepositInsuranceCorporationPremiumExpense	12904000	usd
CY2021	gbci	General Insurance And Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceAndFederalDepositInsuranceCorporationPremiumExpense	8249000	usd
CY2023	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	9731000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	10658000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	10271000	usd
CY2023	us-gaap	Other Noninterest Expense OtherNoninterestExpense	86988000	usd
CY2022	us-gaap	Other Noninterest Expense OtherNoninterestExpense	87518000	usd
CY2021	us-gaap	Other Noninterest Expense OtherNoninterestExpense	70609000	usd
CY2023	us-gaap	Noninterest Expense NoninterestExpense	527358000	usd
CY2022	us-gaap	Noninterest Expense NoninterestExpense	518868000	usd
CY2021	us-gaap	Noninterest Expense NoninterestExpense	434822000	usd
CY2023	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	267608000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	370280000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	349438000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	44681000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	67078000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	64681000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	222927000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	303202000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	284757000	usd
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.01
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.74
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.87
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.01
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.74
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.86
CY2023	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.32
CY2022	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.32
CY2021	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.37
CY2023	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	110864501	shares
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	110757473	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	99313255	shares
CY2023	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	110890447	shares
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	110827933	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	99398250	shares
CY2023	us-gaap	Net Income Loss NetIncomeLoss	222927000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	303202000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	284757000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	125231000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-672570000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-151426000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-31000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	1336000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	790000	usd
CY2023	us-gaap	Oci Debt Securities Available For Sale Transfer To Held To Maturity Adjustment From Aoci For Amortization Of Gain Loss Before Tax OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax	-5612000	usd
CY2022	us-gaap	Oci Debt Securities Available For Sale Transfer To Held To Maturity Adjustment From Aoci For Amortization Of Gain Loss Before Tax OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax	-2990000	usd
CY2021	us-gaap	Oci Debt Securities Available For Sale Transfer To Held To Maturity Adjustment From Aoci For Amortization Of Gain Loss Before Tax OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax	3551000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	34264000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-169540000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-39362000	usd
CY2023	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	96610000	usd
CY2022	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-501376000	usd
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-116405000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	2006000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	7809000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	901000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	4605000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	817000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Reclassification For Discontinuance Before Tax OtherComprehensiveIncomeLossCashFlowHedgeReclassificationForDiscontinuanceBeforeTax	0	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-668000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	1767000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	227000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-1931000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	5225000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	674000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	94679000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-496151000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-115731000	usd
CY2023	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	317606000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-192949000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	169026000	usd
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	2307041000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	284757000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-115731000	usd
CY2021	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.37
CY2021	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	142359000	usd
CY2021	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	839853000	usd
CY2021	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	usd
CY2021	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	4061000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	3177622000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	303202000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-496151000	usd
CY2022	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.32
CY2022	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	146560000	usd
CY2022	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	usd
CY2022	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	5192000	usd
CY2023	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	usd
CY2023	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	6100000	usd
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	3020281000	usd
CY2023	us-gaap	Net Income Loss NetIncomeLoss	222927000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	303202000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	284757000	usd
CY2023	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	14795000	usd
CY2022	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	19963000	usd
CY2021	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	23076000	usd
CY2023	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-15506000	usd
CY2022	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-29587000	usd
CY2021	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-47299000	usd
CY2023	gbci	Accretion Amortization Of Discounts And Premiums Business Combinations AccretionAmortizationOfDiscountsAndPremiumsBusinessCombinations	5347000	usd
CY2022	gbci	Accretion Amortization Of Discounts And Premiums Business Combinations AccretionAmortizationOfDiscountsAndPremiumsBusinessCombinations	-2789000	usd
CY2021	gbci	Accretion Amortization Of Discounts And Premiums Business Combinations AccretionAmortizationOfDiscountsAndPremiumsBusinessCombinations	17881000	usd
CY2023	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	435649000	usd
CY2022	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	743212000	usd
CY2021	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	1550787000	usd
CY2023	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	549778000	usd
CY2022	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	844940000	usd
CY2021	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	1797566000	usd
CY2023	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	12202000	usd
CY2022	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	20032000	usd
CY2021	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	63063000	usd
CY2023	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	1510000	usd
CY2022	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	620000	usd
CY2021	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	-638000	usd
CY2023	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	3849000	usd
CY2022	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	3579000	usd
CY2021	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	2873000	usd
CY2023	us-gaap	Share Based Compensation ShareBasedCompensation	5929000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	5366000	usd
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	4349000	usd
CY2023	us-gaap	Depreciation Nonproduction DepreciationNonproduction	27412000	usd
CY2022	us-gaap	Depreciation Nonproduction DepreciationNonproduction	25830000	usd
CY2021	us-gaap	Depreciation Nonproduction DepreciationNonproduction	21768000	usd
CY2023	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	321000	usd
CY2022	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	121000	usd
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	105000	usd
CY2023	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	507000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	2177000	usd
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-9095000	usd
CY2023	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	9731000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	10658000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	10271000	usd
CY2023	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	20515000	usd
CY2022	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	16640000	usd
CY2021	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	13457000	usd
CY2023	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	10989000	usd
CY2022	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	6865000	usd
CY2021	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-5118000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	9801000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	25807000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-8188000	usd
CY2023	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	121576000	usd
CY2022	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	1922000	usd
CY2021	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-1222000	usd
CY2023	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-8293000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	7822000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	588000	usd
CY2023	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	500715000	usd
CY2022	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	470660000	usd
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	572049000	usd
CY2023	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	29972000	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	326302000	usd
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	usd
CY2023	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	621878000	usd
CY2022	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1101420000	usd
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1453049000	usd
CY2023	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	0	usd
CY2022	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	471581000	usd
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	6315164000	usd
CY2023	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	209909000	usd
CY2022	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	211700000	usd
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	48955000	usd
CY2023	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	0	usd
CY2022	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	523060000	usd
CY2021	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	222695000	usd
CY2023	us-gaap	Proceeds From Collection Of Finance Receivables ProceedsFromCollectionOfFinanceReceivables	2946294000	usd
CY2022	us-gaap	Proceeds From Collection Of Finance Receivables ProceedsFromCollectionOfFinanceReceivables	5432753000	usd
CY2021	us-gaap	Proceeds From Collection Of Finance Receivables ProceedsFromCollectionOfFinanceReceivables	6529504000	usd
CY2023	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	4013701000	usd
CY2022	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	7296411000	usd
CY2021	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	7000632000	usd
CY2023	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	49283000	usd
CY2022	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	23238000	usd
CY2021	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	9436000	usd
CY2023	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	391000	usd
CY2022	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	1014000	usd
CY2021	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	3313000	usd
CY2023	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	630584000	usd
CY2022	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	366467000	usd
CY2021	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	4218000	usd
CY2023	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	559601000	usd
CY2022	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	438398000	usd
CY2021	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	2000	usd
CY2023	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1787000	usd
CY2022	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	2217000	usd
CY2021	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	2112000	usd
CY2023	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	25722000	usd
CY2022	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	40967000	usd
CY2021	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	22640000	usd
CY2023	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	usd
CY2022	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	usd
CY2021	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-1622717000	usd
CY2023	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-207492000	usd
CY2022	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1351782000	usd
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-3906701000	usd
CY2023	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-676652000	usd
CY2022	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-729707000	usd
CY2021	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	3266304000	usd
CY2023	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	540934000	usd
CY2022	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	-74878000	usd
CY2021	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	16211000	usd
CY2023	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	-1800000000	usd
CY2022	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	1800000000	usd
CY2021	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	0	usd
CY2023	us-gaap	Proceeds From Short Term Debt ProceedsFromShortTermDebt	2740000000	usd
CY2022	us-gaap	Proceeds From Short Term Debt ProceedsFromShortTermDebt	0	usd
CY2021	us-gaap	Proceeds From Short Term Debt ProceedsFromShortTermDebt	0	usd
CY2023	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	3327000	usd
CY2022	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	9120000	usd
CY2021	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	3526000	usd
CY2023	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	146690000	usd
CY2022	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	157540000	usd
CY2021	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	145557000	usd
CY2023	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1795000	usd
CY2022	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1704000	usd
CY2021	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1553000	usd
CY2023	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	0	usd
CY2022	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	140000	usd
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	265000	usd
CY2023	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	659124000	usd
CY2022	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	845431000	usd
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	3139196000	usd
CY2023	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	952347000	usd
CY2022	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-35691000	usd
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-195456000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	401995000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	437686000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	633142000	usd
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1354342000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	401995000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	437686000	usd
CY2023	us-gaap	Interest Paid Net InterestPaidNet	204397000	usd
CY2022	us-gaap	Interest Paid Net InterestPaidNet	39339000	usd
CY2021	us-gaap	Interest Paid Net InterestPaidNet	19779000	usd
CY2023	us-gaap	Income Taxes Paid IncomeTaxesPaid	27932000	usd
CY2022	us-gaap	Income Taxes Paid IncomeTaxesPaid	55197000	usd
CY2021	us-gaap	Income Taxes Paid IncomeTaxesPaid	67306000	usd
CY2023	us-gaap	Transfer Of Investments TransferOfInvestments	0	usd
CY2022	us-gaap	Transfer Of Investments TransferOfInvestments	2154475000	usd
CY2021	us-gaap	Transfer Of Investments TransferOfInvestments	844020000	usd
CY2023	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	22000	usd
CY2022	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	0	usd
CY2021	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	0	usd
CY2023	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	1563000	usd
CY2022	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	907000	usd
CY2021	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	1482000	usd
CY2023	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1979000	usd
CY2022	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	25048000	usd
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	801000	usd
CY2023	gbci	Dividends Declared But Not Paid During The Period DividendsDeclaredButNotPaidDuringThePeriod	370000	usd
CY2022	gbci	Dividends Declared But Not Paid During The Period DividendsDeclaredButNotPaidDuringThePeriod	346000	usd
CY2021	gbci	Dividends Declared But Not Paid During The Period DividendsDeclaredButNotPaidDuringThePeriod	11352000	usd
CY2023	us-gaap	Stock Issued1 StockIssued1	0	usd
CY2022	us-gaap	Stock Issued1 StockIssued1	0	usd
CY2021	us-gaap	Stock Issued1 StockIssued1	839853000	usd
CY2023	gbci	Cash Consideration For Outstanding Shares CashConsiderationForOutstandingShares	0	usd
CY2022	gbci	Cash Consideration For Outstanding Shares CashConsiderationForOutstandingShares	0	usd
CY2021	gbci	Cash Consideration For Outstanding Shares CashConsiderationForOutstandingShares	9000	usd
CY2023	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	0	usd
CY2022	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	0	usd
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	4131662000	usd
CY2023	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	0	usd
CY2022	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	0	usd
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	3291800000	usd
CY2023	us-gaap	Use Of Estimates UseOfEstimates	<div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Material estimates that are particularly susceptible to significant change include: 1) the determination of the allowance for credit losses (“ACL” or “allowance”) on loans; 2) the valuation of debt securities; 3) the valuation of real estate acquired in connection with foreclosures or in satisfaction of loans; and 4) the evaluation of goodwill impairment. For the determination of the ACL on loans and real estate valuation estimates, management obtains independent appraisals (new or updated) for significant items. Estimates relating to the investment valuations are obtained from independent third parties. Estimates relating to the evaluation of goodwill for impairment are determined based on internal calculations using independent party inputs.</span></div>
CY2023Q4	gbci	Number Of Bank Divisions NumberOfBankDivisions	17	bankdivision
CY2023	gbci	Maximum Period Of Original Maturity To Be Included In Cash And Cash Equivalents MaximumPeriodOfOriginalMaturityToBeIncludedInCashAndCashEquivalents	P3M
CY2023Q4	us-gaap	Restricted Cash RestrictedCash	17440000	usd
CY2022Q4	us-gaap	Restricted Cash RestrictedCash	0	usd
CY2023Q4	gbci	Federal Reserve Balance Or Cash On Hand Required FederalReserveBalanceOrCashOnHandRequired	0	usd
CY2023	gbci	Minimum Period Past Due To Consider Loans As Delinquent MinimumPeriodPastDueToConsiderLoansAsDelinquent	P30D
CY2023	gbci	Minimum Period Past Due To Consider Loans As Non Accrual MinimumPeriodPastDueToConsiderLoansAsNonAccrual	P90D
CY2023	gbci	Financing Receivable Allowance For Credit Losses Forecasting Period FinancingReceivableAllowanceForCreditLossesForecastingPeriod	4	quarter
CY2023	gbci	Financing Receivable Allowance For Credit Losses Forecasting Period FinancingReceivableAllowanceForCreditLossesForecastingPeriod	4	quarter
CY2023	gbci	Financing Receivable Allowance For Credit Losses Number Of Components FinancingReceivableAllowanceForCreditLossesNumberOfComponents	2	component
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	20790000	usd
CY2022	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	17433000	usd
CY2021	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	16380000	usd
CY2023	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-5995000	usd
CY2022	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	2530000	usd
CY2021	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	6696000	usd
CY2023	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	14795000	usd
CY2022	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	19963000	usd
CY2021	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	23076000	usd
CY2023	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest Allowance For Credit Loss Period Increase Decrease DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossPeriodIncreaseDecrease	0	usd
CY2022	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest Allowance For Credit Loss Period Increase Decrease DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossPeriodIncreaseDecrease	0	usd
CY2021	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest Allowance For Credit Loss Period Increase Decrease DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossPeriodIncreaseDecrease	0	usd
CY2023	gbci	Maximum Term Leases Will Be Considered Short Term MaximumTermLeasesWillBeConsideredShortTerm	P12M
CY2023	gbci	Maximum Period Up To Which Purchase Price Of Business Is Allocated To Assets Acquired And Liabilities Assumed MaximumPeriodUpToWhichPurchasePriceOfBusinessIsAllocatedToAssetsAcquiredAndLiabilitiesAssumed	P1Y
CY2023	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	88547000	usd
CY2022	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	82850000	usd
CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	65194000	usd
CY2022Q4	us-gaap	Capitalized Contract Cost Accumulated Impairment CapitalizedContractCostAccumulatedImpairment	0	usd
CY2023Q4	us-gaap	Capitalized Contract Cost Accumulated Impairment CapitalizedContractCostAccumulatedImpairment	0	usd
CY2023	gbci	Percentage Of Likelihood For Term More Likely Than Not PercentageOfLikelihoodForTermMoreLikelyThanNot	0.50
CY2023	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	Certain reclassifications have been made to the 2022 and 2021 financial statements to conform to the 2023 presentation.
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	5283253000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	841000	usd
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	498375000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	4785719000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	3502411000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	2843000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	325060000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	3180194000	usd
CY2023Q4	gbci	Debt Securities Amortized Cost Basis DebtSecuritiesAmortizedCostBasis	8785664000	usd
CY2023Q4	gbci	Securities Gross Unrealized Gain Accumulated In Investments SecuritiesGrossUnrealizedGainAccumulatedInInvestments	3684000	usd
CY2023Q4	gbci	Securities Gross Unrealized Loss Accumulated In Investments SecuritiesGrossUnrealizedLossAccumulatedInInvestments	823435000	usd
CY2023Q4	gbci	Debt Securities Fair Value DebtSecuritiesFairValue	7965913000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	5930103000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1085000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	623881000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	5307307000	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	3715052000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	1045000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	441305000	usd
CY2022Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	3274792000	usd
CY2022Q4	gbci	Debt Securities Amortized Cost Basis DebtSecuritiesAmortizedCostBasis	9645155000	usd
CY2022Q4	gbci	Securities Gross Unrealized Gain Accumulated In Investments SecuritiesGrossUnrealizedGainAccumulatedInInvestments	2130000	usd
CY2022Q4	gbci	Securities Gross Unrealized Loss Accumulated In Investments SecuritiesGrossUnrealizedLossAccumulatedInInvestments	1065186000	usd
CY2022Q4	gbci	Debt Securities Fair Value DebtSecuritiesFairValue	8582099000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	3632000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	3653000	usd
CY2023Q4	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	5233000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	5213000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	857022000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	804203000	usd
CY2023Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	927824000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	860978000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	36144000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	35010000	usd
CY2023Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	184556000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	177537000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	39110000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	36885000	usd
CY2023Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	1385660000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	1215724000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	935908000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	879751000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	2503273000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	2259452000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	4347345000	usd
CY2023Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	3905968000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateNetCarryingAmount	999138000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	920742000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	5283253000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	4785719000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	3502411000	usd
CY2023Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	3180194000	usd
CY2023	gbci	Proceeds From Sales And Calls Of Debt Securities Available For Sale ProceedsFromSalesAndCallsOfDebtSecuritiesAvailableForSale	31944000	usd
CY2022	gbci	Proceeds From Sales And Calls Of Debt Securities Available For Sale ProceedsFromSalesAndCallsOfDebtSecuritiesAvailableForSale	428225000	usd
CY2021	gbci	Proceeds From Sales And Calls Of Debt Securities Available For Sale ProceedsFromSalesAndCallsOfDebtSecuritiesAvailableForSale	188431000	usd
CY2023	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	145000	usd
CY2022	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	3357000	usd
CY2021	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	984000	usd
CY2023	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	176000	usd
CY2022	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	2021000	usd
CY2021	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	194000	usd
CY2023	gbci	Held To Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldToMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	18125000	usd
CY2022	gbci	Held To Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldToMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	28210000	usd
CY2021	gbci	Held To Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldToMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	48475000	usd
CY2023	gbci	Held To Maturity Securities Sold Security Realized Gain HeldToMaturitySecuritiesSoldSecurityRealizedGain	10000	usd
CY2022	gbci	Held To Maturity Securities Sold Security Realized Gain HeldToMaturitySecuritiesSoldSecurityRealizedGain	64000	usd
CY2021	gbci	Held To Maturity Securities Sold Security Realized Gain HeldToMaturitySecuritiesSoldSecurityRealizedGain	3000	usd
CY2023	gbci	Held To Maturity Securities Sold Security Realized Loss HeldToMaturitySecuritiesSoldSecurityRealizedLoss	193000	usd
CY2022	gbci	Held To Maturity Securities Sold Security Realized Loss HeldToMaturitySecuritiesSoldSecurityRealizedLoss	780000	usd
CY2021	gbci	Held To Maturity Securities Sold Security Realized Loss HeldToMaturitySecuritiesSoldSecurityRealizedLoss	1431000	usd
CY2023	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	1700000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	713	security
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	29403000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	370000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	4679701000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	498005000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	4709104000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	498375000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	794	security
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	1075458000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	69730000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	4144180000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	554151000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	5219638000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	623881000	usd
CY2023	gbci	Available For Sale Securities In Unrealized Loss Positions Severity Rate AvailableForSaleSecuritiesInUnrealizedLossPositionsSeverityRate	0.05
CY2023Q4	gbci	Number Of Credit Rating Categories Highest NumberOfCreditRatingCategoriesHighest	4	security
CY2023Q4	gbci	Interest Receivable Available For Sale Debt Securities InterestReceivableAvailableForSaleDebtSecurities	9319000	usd
CY2022Q4	gbci	Interest Receivable Available For Sale Debt Securities InterestReceivableAvailableForSaleDebtSecurities	10518000	usd
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0	usd
CY2023Q4	gbci	Number Of Credit Rating Categories Highest NumberOfCreditRatingCategoriesHighest	4	security
CY2023Q4	gbci	Interest Receivable Held To Maturity Debt Securities InterestReceivableHeldToMaturityDebtSecurities	16990000	usd
CY2022Q4	gbci	Interest Receivable Held To Maturity Debt Securities InterestReceivableHeldToMaturityDebtSecurities	17524000	usd
CY2023Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	usd
CY2022Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	16198082000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	15246812000	usd
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	192757000	usd
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	182283000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	16005325000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	15064529000	usd
CY2023Q4	us-gaap	Financing Receivable Unamortized Loan Fee Cost FinancingReceivableUnamortizedLoanFeeCost	25577000	usd
CY2022Q4	us-gaap	Financing Receivable Unamortized Loan Fee Cost FinancingReceivableUnamortizedLoanFeeCost	25882000	usd
CY2023Q4	us-gaap	Financing Receivable Unamortized Purchase Premium Discount FinancingReceivableUnamortizedPurchasePremiumDiscount	13802000	usd
CY2022Q4	us-gaap	Financing Receivable Unamortized Purchase Premium Discount FinancingReceivableUnamortizedPurchasePremiumDiscount	17832000	usd
CY2023Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	67362000	usd
CY2022Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	54971000	usd
CY2023Q4	gbci	Percentage Of Consolidated Stockholders Equity Exceeding Which No Borrower Had Outstanding Loans Or Commitments PercentageOfConsolidatedStockholdersEquityExceedingWhichNoBorrowerHadOutstandingLoansOrCommitments	0.10
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	16198082000	usd
CY2022Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	15246812000	usd
CY2023	us-gaap	Financing Receivable Accrued Interest Writeoff FinancingReceivableAccruedInterestWriteoff	356000	usd
CY2022	us-gaap	Financing Receivable Accrued Interest Writeoff FinancingReceivableAccruedInterestWriteoff	1175000	usd
CY2021	us-gaap	Financing Receivable Accrued Interest Writeoff FinancingReceivableAccruedInterestWriteoff	660000	usd
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Modified Period FinancingReceivableExcludingAccruedInterestModifiedPeriod	60559000	usd
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Modified Past12 Months FinancingReceivableExcludingAccruedInterestModifiedPast12Months	60559000	usd
CY2023Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	5361000	usd
CY2023Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	98000	usd
CY2022Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	270000	usd
CY2022	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	11	loan
CY2022	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	5616000	usd
CY2022	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	6346000	usd
CY2021	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	12	loan
CY2021	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	2442000	usd
CY2021	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	2442000	usd
CY2022Q4	gbci	Tdr With Pre Modification Loan Balance For Which Oreo Was Received TDRWithPreModificationLoanBalanceForWhichOreoWasReceived	1253000	usd
CY2021Q4	gbci	Tdr With Pre Modification Loan Balance For Which Oreo Was Received TDRWithPreModificationLoanBalanceForWhichOreoWasReceived	1628000	usd
CY2022Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	437000	usd
CY2021	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	0	usd
CY2022	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	0	usd
CY2023Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	201159000	usd
CY2022Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	184851000	usd
CY2023Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	356728000	usd
CY2022Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	327055000	usd
CY2023Q4	gbci	Right Of Use Asset RightOfUseAsset	65063000	usd
CY2022Q4	gbci	Right Of Use Asset RightOfUseAsset	71045000	usd
CY2023Q4	gbci	Property Plant And Equipment And Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	421791000	usd
CY2022Q4	gbci	Property Plant And Equipment And Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	398100000	usd
CY2023	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	913000	usd
CY2022	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	0	usd
CY2023Q4	us-gaap	Finance Lease Right Of Use Asset Before Accumulated Amortization FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization	31222000	usd
CY2022Q4	us-gaap	Finance Lease Right Of Use Asset Before Accumulated Amortization FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization	30254000	usd
CY2023Q4	us-gaap	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	6940000	usd
CY2022Q4	us-gaap	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	2760000	usd
CY2023Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	24282000	usd
CY2023Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	40781000	usd
CY2022Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	27494000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	43551000	usd
CY2023Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	25116000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	44319000	usd
CY2022Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	28204000	usd
CY2022Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	46579000	usd
CY2023Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P11Y
CY2023Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P16Y
CY2022Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P12Y
CY2022Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P17Y
CY2023Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.036
CY2023Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.037
CY2022Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.036
CY2022Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.036
CY2023Q4	us-gaap	Finance Lease Liability Payments Due In Next Rolling Twelve Months FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths	4685000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Rolling Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths	4623000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due In Rolling Year Two FinanceLeaseLiabilityPaymentsDueInRollingYearTwo	4669000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Two LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo	4756000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due In Rolling Year Three FinanceLeaseLiabilityPaymentsDueInRollingYearThree	4679000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Three LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree	4580000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due In Rolling Year Four FinanceLeaseLiabilityPaymentsDueInRollingYearFour	4688000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Four LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour	4301000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due In Rolling Year Five FinanceLeaseLiabilityPaymentsDueInRollingYearFive	578000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Five LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive	3768000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due In Rolling After Year Five FinanceLeaseLiabilityPaymentsDueInRollingAfterYearFive	11135000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Rolling Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive	39043000	usd
CY2023Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	30434000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	61071000	usd
CY2023Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	3847000	usd
CY2023Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	3078000	usd
CY2023Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	21269000	usd
CY2023Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	41241000	usd
CY2023Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	25116000	usd
CY2023Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	44319000	usd
CY2023Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	5318000	usd
CY2023Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	16752000	usd
CY2023	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	4201000	usd
CY2022	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	2249000	usd
CY2023	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	958000	usd
CY2022	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	565000	usd
CY2023	us-gaap	Operating Lease Cost OperatingLeaseCost	5531000	usd
CY2022	us-gaap	Operating Lease Cost OperatingLeaseCost	5927000	usd
CY2023	us-gaap	Short Term Lease Cost ShortTermLeaseCost	633000	usd
CY2022	us-gaap	Short Term Lease Cost ShortTermLeaseCost	428000	usd
CY2023	us-gaap	Variable Lease Cost VariableLeaseCost	1666000	usd
CY2022	us-gaap	Variable Lease Cost VariableLeaseCost	1291000	usd
CY2023	us-gaap	Sublease Income SubleaseIncome	39000	usd
CY2022	us-gaap	Sublease Income SubleaseIncome	43000	usd
CY2023	us-gaap	Lease Cost LeaseCost	12950000	usd
CY2022	us-gaap	Lease Cost LeaseCost	10417000	usd
CY2023	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	958000	usd
CY2023	us-gaap	Operating Lease Payments OperatingLeasePayments	3500000	usd
CY2022	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	566000	usd
CY2022	us-gaap	Operating Lease Payments OperatingLeasePayments	3961000	usd
CY2023	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	3588000	usd
CY2022	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	2355000	usd
CY2023	us-gaap	Servicing Asset At Amortized Value Additions ServicingAssetAtAmortizedValueAdditions	434000	usd
CY2022	us-gaap	Servicing Asset At Amortized Value Additions ServicingAssetAtAmortizedValueAdditions	2461000	usd
CY2021	us-gaap	Servicing Asset At Amortized Value Additions ServicingAssetAtAmortizedValueAdditions	4435000	usd
CY2021	gbci	Servicing Asset At Amortized Cost Acquisitions ServicingAssetAtAmortizedCostAcquisitions	1354000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	985393000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	985393000	usd
CY2020Q4	us-gaap	Goodwill Goodwill	514013000	usd
CY2023	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	usd
CY2022	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	usd
CY2021	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	471380000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	985393000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	985393000	usd
CY2023Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	40159000	usd
CY2022Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	40159000	usd
CY2022Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	13488000	usd
CY2021Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	12839000	usd
CY2020Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	8976000	usd
CY2023	gbci	Servicing Asset At Amortized Cost Acquisitions ServicingAssetAtAmortizedCostAcquisitions	0	usd
CY2022	gbci	Servicing Asset At Amortized Cost Acquisitions ServicingAssetAtAmortizedCostAcquisitions	0	usd
CY2023	us-gaap	Servicing Asset At Amortized Value Amortization1 ServicingAssetAtAmortizedValueAmortization1	1388000	usd
CY2021Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	12839000	usd
CY2022Q4	us-gaap	Servicing Asset ServicingAsset	1661294000	usd
CY2021Q4	us-gaap	Servicing Asset ServicingAsset	1639058000	usd
CY2023Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	18000000	usd
CY2022Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	19716000	usd
CY2021Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	16938000	usd
CY2023Q4	us-gaap	Cash Fdic Insured Amount CashFDICInsuredAmount	250000	usd
CY2023Q4	gbci	Time Deposits That Meet Or Exceed Fdic Insurance Limit TimeDepositsThatMeetOrExceedFDICInsuranceLimit	1227607000	usd
CY2022Q4	gbci	Time Deposits That Meet Or Exceed Fdic Insurance Limit TimeDepositsThatMeetOrExceedFDICInsuranceLimit	243219000	usd
CY2023Q4	us-gaap	Deposits Wholesale DepositsWholesale	0	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	2712004000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	138299000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	33770000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	18684000	usd
CY2023Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	12636000	usd
CY2023Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	0	usd
CY2023Q4	us-gaap	Time Deposits TimeDeposits	2915393000	usd
CY2023Q4	gbci	Overdraft Demand Deposits Reclassified As Loans OverdraftDemandDepositsReclassifiedAsLoans	8242000	usd
CY2022Q4	gbci	Overdraft Demand Deposits Reclassified As Loans OverdraftDemandDepositsReclassifiedAsLoans	8737000	usd
CY2023Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	31706000	usd
CY2022Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	37046000	usd
CY2023Q4	us-gaap	Securities Sold Under Agreements To Repurchase Gross Including Not Subject To Master Netting Arrangement SecuritiesSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	1486850000	usd
CY2022Q4	us-gaap	Securities Sold Under Agreements To Repurchase Gross Including Not Subject To Master Netting Arrangement SecuritiesSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	945916000	usd
CY2023Q4	us-gaap	Federal Home Loan Bank Advances Branch Of Fhlb Bank Amount Of Advances By Branch FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch	0	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Advances Branch Of Fhlb Bank Amount Of Advances By Branch FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch	1800000000	usd
CY2022Q4	us-gaap	Federal Home Loan Bank Advances Weighted Average Interest Rate FederalHomeLoanBankAdvancesWeightedAverageInterestRate	0.0454
CY2023Q4	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	565000000	usd
CY2023	gbci	Maximum Number Of Consecutive Quarters For Deferral Of Interest Payments On Trust Preferred Securities MaximumNumberOfConsecutiveQuartersForDeferralOfInterestPaymentsOnTrustPreferredSecurities	20	quarter
CY2023Q4	gbci	Size Of Company Eligible For Tier1 Grandfather Provision SizeOfCompanyEligibleForTier1GrandfatherProvision	15000000000	usd
CY2022Q4	gbci	Size Of Company Eligible For Tier1 Grandfather Provision SizeOfCompanyEligibleForTier1GrandfatherProvision	15000000000	usd
CY2023Q4	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	3807239000	usd
CY2023Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	-17988000	usd
CY2023Q4	gbci	Capital Conservation Buffer To Risk Weighted Assets Current Year CapitalConservationBufferToRiskWeightedAssetsCurrentYear	0.025
CY2023Q4	us-gaap	Capital Capital	2724988000	usd
CY2023Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1461
CY2023Q4	us-gaap	Capital Required For Capital Adequacy CapitalRequiredForCapitalAdequacy	1492211000	usd
CY2023Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2023Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	2397716000	usd
CY2023Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.1285
CY2023Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy TierOneRiskBasedCapitalRequiredForCapitalAdequacy	1119158000	usd
CY2023Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2023Q4	us-gaap	Common Equity Tier One Capital CommonEquityTierOneCapital	2397716000	usd
CY2023Q4	us-gaap	Common Equity Tier One Capital Ratio CommonEquityTierOneCapitalRatio	0.1285
CY2023Q4	us-gaap	Common Equity Tier One Capital Required For Capital Adequacy CommonEquityTierOneCapitalRequiredForCapitalAdequacy	839369000	usd
CY2023Q4	gbci	Tier One Common Capital Required For Capital Adequacy To Risk Weighted Assets TierOneCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0450
CY2023Q4	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	2397716000	usd
CY2023Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.0871
CY2023Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy TierOneLeverageCapitalRequiredForCapitalAdequacy	1101349000	usd
CY2023Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2022Q4	us-gaap	Capital Capital	2629557000	usd
CY2022Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1402
CY2022Q4	us-gaap	Capital Required For Capital Adequacy CapitalRequiredForCapitalAdequacy	1500096000	usd
CY2022Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2022Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	2314322000	usd
CY2022Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.1234
CY2022Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy TierOneRiskBasedCapitalRequiredForCapitalAdequacy	1125072000	usd
CY2022Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2022Q4	us-gaap	Common Equity Tier One Capital CommonEquityTierOneCapital	2314322000	usd
CY2022Q4	us-gaap	Common Equity Tier One Capital Ratio CommonEquityTierOneCapitalRatio	0.1234
CY2022Q4	us-gaap	Common Equity Tier One Capital Required For Capital Adequacy CommonEquityTierOneCapitalRequiredForCapitalAdequacy	843804000	usd
CY2022Q4	gbci	Tier One Common Capital Required For Capital Adequacy To Risk Weighted Assets TierOneCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0450
CY2022Q4	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	2314322000	usd
CY2022Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.0879
CY2022Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy TierOneLeverageCapitalRequiredForCapitalAdequacy	1053214000	usd
CY2022Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2023Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	1472284	shares
CY2023	gbci	Consulting Fees ConsultingFees	16947000	usd
CY2022	gbci	Consulting Fees ConsultingFees	15719000	usd
CY2021	gbci	Consulting Fees ConsultingFees	11297000	usd
CY2023	gbci	Debit Card Expense DebitCardExpense	12189000	usd
CY2022	gbci	Debit Card Expense DebitCardExpense	9317000	usd
CY2021	gbci	Debit Card Expense DebitCardExpense	5722000	usd
CY2023	gbci	Loan Related Expenses LoanRelatedExpenses	8135000	usd
CY2022	gbci	Loan Related Expenses LoanRelatedExpenses	7688000	usd
CY2021	gbci	Loan Related Expenses LoanRelatedExpenses	7438000	usd
CY2023	gbci	Vie Write Downs Losses And Other Expenses VIEWriteDownsLossesAndOtherExpenses	7333000	usd
CY2022	gbci	Vie Write Downs Losses And Other Expenses VIEWriteDownsLossesAndOtherExpenses	7229000	usd
CY2021	gbci	Vie Write Downs Losses And Other Expenses VIEWriteDownsLossesAndOtherExpenses	6323000	usd
CY2023	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	6227000	usd
CY2022	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	5811000	usd
CY2021	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	3527000	usd
CY2023	gbci	Telephone Expenses TelephoneExpenses	6109000	usd
CY2022	gbci	Telephone Expenses TelephoneExpenses	6577000	usd
CY2021	gbci	Telephone Expenses TelephoneExpenses	5631000	usd
CY2023	us-gaap	Business Development BusinessDevelopment	5630000	usd
CY2022	us-gaap	Business Development BusinessDevelopment	5893000	usd
CY2021	us-gaap	Business Development BusinessDevelopment	5250000	usd
CY2023	us-gaap	Postage Expense PostageExpense	4300000	usd
CY2022	us-gaap	Postage Expense PostageExpense	4095000	usd
CY2021	us-gaap	Postage Expense PostageExpense	3681000	usd
CY2023	us-gaap	Supplies Expense SuppliesExpense	3130000	usd
CY2022	us-gaap	Supplies Expense SuppliesExpense	4026000	usd
CY2021	us-gaap	Supplies Expense SuppliesExpense	3334000	usd
CY2023	gbci	Deposit Related Expenses DepositRelatedExpenses	2781000	usd
CY2022	gbci	Deposit Related Expenses DepositRelatedExpenses	2284000	usd
CY2021	gbci	Deposit Related Expenses DepositRelatedExpenses	2020000	usd
CY2023	gbci	Accounting Fees AccountingFees	1956000	usd
CY2022	gbci	Accounting Fees AccountingFees	2005000	usd
CY2021	gbci	Accounting Fees AccountingFees	1538000	usd
CY2023	us-gaap	Legal Fees LegalFees	1490000	usd
CY2022	us-gaap	Legal Fees LegalFees	2210000	usd
CY2021	us-gaap	Legal Fees LegalFees	1391000	usd
CY2023	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	1300000	usd
CY2022	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	9957000	usd
CY2021	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	9830000	usd
CY2023	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-160000	usd
CY2022	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	3047000	usd
CY2021	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	950000	usd
CY2023	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	9301000	usd
CY2022	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	7754000	usd
CY2021	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	4577000	usd
CY2023	us-gaap	Other Noninterest Expense OtherNoninterestExpense	86988000	usd
CY2022	us-gaap	Other Noninterest Expense OtherNoninterestExpense	87518000	usd
CY2021	us-gaap	Other Noninterest Expense OtherNoninterestExpense	70609000	usd
CY2023	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	27626000	usd
CY2022	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	42951000	usd
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	51180000	usd
CY2023	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	16548000	usd
CY2022	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	21950000	usd
CY2021	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	22596000	usd
CY2023	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	44174000	usd
CY2022	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	64901000	usd
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	73776000	usd
CY2023	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	404000	usd
CY2022	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	1712000	usd
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-7151000	usd
CY2023	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	103000	usd
CY2022	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	465000	usd
CY2021	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-1944000	usd
CY2023	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	507000	usd
CY2022	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	2177000	usd
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-9095000	usd
CY2023	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	44681000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	67078000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	64681000	usd
CY2023	us-gaap	Other Tax Expense Benefit OtherTaxExpenseBenefit	-313000	usd
CY2022Q4	gbci	Deferred Tax Liabilities Operating Lease Rou Assets DeferredTaxLiabilitiesOperatingLeaseROUAssets	11004000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	10103000	usd
CY2022	us-gaap	Other Tax Expense Benefit OtherTaxExpenseBenefit	-315000	usd
CY2021	us-gaap	Other Tax Expense Benefit OtherTaxExpenseBenefit	-315000	usd
CY2023	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2022	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2021	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2023	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.049
CY2022	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.048
CY2021	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.047
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.043
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.044
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Exempt Income EffectiveIncomeTaxRateReconciliationTaxExemptIncome	0.042
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.056
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.028
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.048
CY2023	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.007
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.005
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.018
CY2023	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.167
CY2022	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.181
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.185
CY2023Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	124533000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	157381000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	53074000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Provision For Loan Losses DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses	52445000	usd
CY2023Q4	gbci	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	11093000	usd
CY2022Q4	gbci	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	11871000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	9465000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	11024000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	8690000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	8211000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	4502000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Derivative Instruments DeferredTaxAssetsDerivativeInstruments	0	usd
CY2023Q4	us-gaap	Deferred Tax Assets Equity Method Investments DeferredTaxAssetsEquityMethodInvestments	3606000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Equity Method Investments DeferredTaxAssetsEquityMethodInvestments	4932000	usd
CY2023Q4	gbci	Deferred Tax Asset Debt Securities Available For Sale Transferred DeferredTaxAssetDebtSecuritiesAvailableForSaleTransferred	1601000	usd
CY2022Q4	gbci	Deferred Tax Asset Debt Securities Available For Sale Transferred DeferredTaxAssetDebtSecuritiesAvailableForSaleTransferred	3017000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	919000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	1253000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	4112000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	2376000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	221595000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	252510000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	17728000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	17091000	usd
CY2023Q4	gbci	Deferred Tax Liabilities Operating Lease Rou Assets DeferredTaxLiabilitiesOperatingLeaseROUAssets	10207000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	284757000	usd
CY2023	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	110864501	shares
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	110757473	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	99313255	shares
CY2022Q4	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	10083000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	6014000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	8212000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	4502000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Derivatives DeferredTaxLiabilitiesDerivatives	0	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	3137000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Mortgage Servicing Rights DeferredTaxLiabilitiesMortgageServicingRights	3408000	usd
CY2023Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	10834000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	9525000	usd
CY2023Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	62525000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	59323000	usd
CY2023Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	159070000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	193187000	usd
CY2023Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	usd
CY2023Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	0	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	0	usd
CY2023Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	0	usd
CY2022Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	0	usd
CY2021	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	-112487000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-115731000	usd
CY2022	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	-496775000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-496151000	usd
CY2023	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	93912000	usd
CY2023	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	94679000	usd
CY2023	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	222927000	usd
CY2023	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	222927000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	303202000	usd
CY2022	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	303202000	usd
CY2021	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	284757000	usd
CY2023Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	171980000	usd
CY2023	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	25946	shares
CY2022	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	70460	shares
CY2021	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	84995	shares
CY2023	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	110890447	shares
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	110827933	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	99398250	shares
CY2023	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.01
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.74
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.87
CY2023	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.01
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.74
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.86
CY2023	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	223626	shares
CY2022	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	8642	shares
CY2021	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	194	shares
CY2023Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	231888000	usd
CY2023Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	247365000	usd
CY2023Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	264906000	usd
CY2023Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	273496000	usd
CY2023Q1	us-gaap	Interest Expense InterestExpense	45696000	usd
CY2023Q2	us-gaap	Interest Expense InterestExpense	75385000	usd
CY2023Q3	us-gaap	Interest Expense InterestExpense	97852000	usd
CY2023Q4	us-gaap	Interest Expense InterestExpense	107040000	usd
CY2023Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	186192000	usd
CY2023Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	167054000	usd
CY2023Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	166456000	usd
CY2023Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	5470000	usd
CY2023Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	2773000	usd
CY2023Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	3539000	usd
CY2023Q4	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	3013000	usd
CY2023Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	180722000	usd
CY2023Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	169207000	usd
CY2023Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	163515000	usd
CY2023Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	163443000	usd
CY2023Q1	us-gaap	Noninterest Income NoninterestIncome	27895000	usd
CY2023Q2	us-gaap	Noninterest Income NoninterestIncome	29079000	usd
CY2023Q3	us-gaap	Noninterest Income NoninterestIncome	30240000	usd
CY2023Q4	us-gaap	Noninterest Income NoninterestIncome	30865000	usd
CY2023Q1	us-gaap	Noninterest Expense NoninterestExpense	134982000	usd
CY2023Q2	us-gaap	Noninterest Expense NoninterestExpense	130604000	usd
CY2023Q3	us-gaap	Noninterest Expense NoninterestExpense	129576000	usd
CY2023Q4	us-gaap	Noninterest Expense NoninterestExpense	132196000	usd
CY2023Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	73635000	usd
CY2023Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	67682000	usd
CY2023Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	64179000	usd
CY2023Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	62112000	usd
CY2023Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	12424000	usd
CY2023Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	12727000	usd
CY2023Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	11734000	usd
CY2023Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7796000	usd
CY2023Q1	us-gaap	Net Income Loss NetIncomeLoss	61211000	usd
CY2023Q2	us-gaap	Net Income Loss NetIncomeLoss	54955000	usd
CY2023Q3	us-gaap	Net Income Loss NetIncomeLoss	52445000	usd
CY2023Q4	us-gaap	Net Income Loss NetIncomeLoss	54316000	usd
CY2023Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.55
CY2023Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.50
CY2023Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.47
CY2023Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.49
CY2023Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.55
CY2023Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.50
CY2023Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.47
CY2023Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.49
CY2022Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	190516000	usd
CY2022Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	199637000	usd
CY2022Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	214402000	usd
CY2022Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	225085000	usd
CY2022Q1	us-gaap	Interest Expense InterestExpense	4961000	usd
CY2022Q2	us-gaap	Interest Expense InterestExpense	6199000	usd
CY2022Q3	us-gaap	Interest Expense InterestExpense	9075000	usd
CY2022Q4	us-gaap	Interest Expense InterestExpense	21026000	usd
CY2022Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	185555000	usd
CY2022Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	193438000	usd
CY2022Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	205327000	usd
CY2022Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	204059000	usd
CY2022Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	7031000	usd
CY2022Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	-1533000	usd
CY2022Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	8341000	usd
CY2022Q4	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6124000	usd
CY2022Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	178524000	usd
CY2022Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	194971000	usd
CY2022Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	196986000	usd
CY2022Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	197935000	usd
CY2022Q1	us-gaap	Noninterest Income NoninterestIncome	33563000	usd
CY2022Q2	us-gaap	Noninterest Income NoninterestIncome	28280000	usd
CY2022Q3	us-gaap	Noninterest Income NoninterestIncome	30406000	usd
CY2022Q4	us-gaap	Noninterest Income NoninterestIncome	28483000	usd
CY2022Q1	us-gaap	Noninterest Expense NoninterestExpense	130308000	usd
CY2022Q2	us-gaap	Noninterest Expense NoninterestExpense	129521000	usd
CY2022Q3	us-gaap	Noninterest Expense NoninterestExpense	130060000	usd
CY2022Q4	us-gaap	Noninterest Expense NoninterestExpense	128979000	usd
CY2022Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	81779000	usd
CY2022Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	93730000	usd
CY2022Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	97332000	usd
CY2022Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	97439000	usd
CY2022Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	13984000	usd
CY2022Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	17338000	usd
CY2022Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	17994000	usd
CY2022Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	17762000	usd
CY2022Q1	us-gaap	Net Income Loss NetIncomeLoss	67795000	usd
CY2022Q2	us-gaap	Net Income Loss NetIncomeLoss	76392000	usd
CY2022Q3	us-gaap	Net Income Loss NetIncomeLoss	79338000	usd
CY2022Q4	us-gaap	Net Income Loss NetIncomeLoss	79677000	usd
CY2022Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.61
CY2022Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.69
CY2022Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.72
CY2022Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.72
CY2022Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.61
CY2022Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.69
CY2022Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.72
CY2022Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.72
CY2021	gbci	Fair Value Measurement Transfers From One Level To Another FairValueMeasurementTransfersFromOneLevelToAnother	0	usd
CY2022	gbci	Fair Value Measurement Transfers From One Level To Another FairValueMeasurementTransfersFromOneLevelToAnother	0	usd
CY2023	gbci	Fair Value Measurement Transfers From One Level To Another FairValueMeasurementTransfersFromOneLevelToAnother	0	usd
CY2023Q4	us-gaap	Other Commitment OtherCommitment	4162338000	usd
CY2022Q4	us-gaap	Other Commitment OtherCommitment	4829718000	usd
CY2023	dei	Auditor Firm AuditorFirmId	686

Files In Submission

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$GBCI
GLACIER BANCORP, INC. Stock $gbci

2024 Q1 Form 10-K Financial Statement

#000086867124000042 Filed on February 23, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$GBCI GLACIER BANCORP, INC. Stock $gbci

2024 Q1 Form 10-K Financial Statement

#000086867124000042 Filed on February 23, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$GBCI
GLACIER BANCORP, INC. Stock $gbci