$GBCI
GLACIER BANCORP, INC. Stock $gbci

$gbci Overview Financials Valuation SEC Filings Company Website

2021 Q4 Form 10-Q Financial Statement

#000086867121000089 Filed on November 01, 2021

Income Statement

Concept	2021 Q4	2021 Q3	2020 Q3
Revenue	$192.8M	$166.7M	$157.5M
YoY Change	12.56%	5.88%	10.6%
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	$9.000M	$7.700M	$7.900M
YoY Change	13.92%	-2.53%	12.86%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$5.203M	$4.128M	$6.084M
YoY Change	-6.25%	-32.15%	-44.42%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$59.98M	$92.60M	$96.51M
YoY Change	-40.5%	-4.06%	51.22%
Income Tax	$9.272M	$16.98M	$18.75M
% Of Pretax Income	15.46%	18.33%	19.43%
Net Earnings	$50.71M	$75.62M	$77.76M
YoY Change	-38.05%	-2.75%	50.66%
Net Earnings / Revenue	26.3%	45.35%	49.37%
Basic Earnings Per Share	$0.46	$0.79	$0.81
Diluted Earnings Per Share	$0.46	$0.79	$0.81
COMMON SHARES
Basic Shares Outstanding	110.7M shares	95.51M shares	95.41M shares
Diluted Shares Outstanding		95.59M shares	95.44M shares

Balance Sheet

Concept	2021 Q4	2021 Q3	2020 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$437.7M	$348.9M	$769.9M
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	$322.4M	$316.0M	$326.9M
YoY Change	18.19%	-3.34%	6.29%
Goodwill	$985.4M	$514.0M	$514.0M
YoY Change	91.71%	0.0%	12.62%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$28.00M		$0.00
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$25.94B	$21.31B	$17.93B
YoY Change	40.19%	18.9%	30.67%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$2.000M	$2.000M	$4.000M
YoY Change	-33.33%	-50.0%	0.0%
Accrued Expenses	$48.00M	$48.00M	$50.00M
YoY Change	-4.0%	-4.0%	13.64%
Deferred Revenue
YoY Change
Short-Term Debt	$1.021B	$1.041B	$966.0M
YoY Change	1.59%	7.76%	72.81%
Long-Term Debt Due	$0.00	$0.00	$0.00
YoY Change
Total Short-Term Liabilities	$50.00M	$50.00M	$54.00M
YoY Change	-5.66%	-7.41%	12.5%
LONG-TERM LIABILITIES
Long-Term Debt	$177.0M	$166.0M	$173.0M
YoY Change	2.31%	-4.05%	11.61%
Other Long-Term Liabilities	$178.0M	$164.0M	$154.0M
YoY Change	22.76%	6.49%	22.22%
Total Long-Term Liabilities	$355.0M	$330.0M	$327.0M
YoY Change	11.64%	0.92%	16.37%
TOTAL LIABILITIES
Total Short-Term Liabilities	$50.00M	$50.00M	$54.00M
Total Long-Term Liabilities	$355.0M	$330.0M	$327.0M
Total Liabilities	$22.76B	$18.93B	$15.67B
YoY Change	40.54%	20.77%	33.2%
SHAREHOLDERS EQUITY
Retained Earnings	$810.3M	$811.1M	$629.1M
YoY Change	21.32%	28.92%	19.01%
Common Stock	$2.339B	$1.498B	$1.494B
YoY Change	56.44%	0.27%	8.59%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$3.178B	$2.388B	$2.255B
YoY Change
Total Liabilities & Shareholders Equity	$25.94B	$21.31B	$17.93B
YoY Change	40.19%	18.9%	30.67%

Cashflow Statement

Concept	2021 Q4	2021 Q3	2020 Q3
OPERATING ACTIVITIES
Net Income	$50.71M	$75.62M	$77.76M
YoY Change	-38.05%	-2.75%	50.66%
Depreciation, Depletion And Amortization	$9.000M	$7.700M	$7.900M
YoY Change	13.92%	-2.53%	12.86%
Cash From Operating Activities	$154.7M	$127.2M	-$23.40M
YoY Change	104.36%	-643.59%	-181.53%
INVESTING ACTIVITIES
Capital Expenditures	-$5.200M	-$4.200M	-$3.200M
YoY Change	44.44%	31.25%	39.13%
Acquisitions
YoY Change
Other Investing Activities	-$540.6M	-$1.453B	-$696.1M
YoY Change	-20.65%	108.75%	-632.59%
Cash From Investing Activities	-$545.8M	-$1.457B	-$699.3M
YoY Change	-20.31%	108.39%	-645.05%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	479.8M	757.8M	945.0M
YoY Change	1.59%	-19.81%	5120.99%
NET CHANGE
Cash From Operating Activities	154.7M	127.2M	-23.40M
Cash From Investing Activities	-545.8M	-1.457B	-699.3M
Cash From Financing Activities	479.8M	757.8M	945.0M
Net Change In Cash	88.70M	-572.3M	222.3M
YoY Change	-164.79%	-357.44%	26.96%
FREE CASH FLOW
Cash From Operating Activities	$154.7M	$127.2M	-$23.40M
Capital Expenditures	-$5.200M	-$4.200M	-$3.200M
Free Cash Flow	$159.9M	$131.4M	-$20.20M
YoY Change	101.64%	-750.5%	-165.16%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Entity Central Index Key EntityCentralIndexKey	0000868671
	dei	Amendment Flag AmendmentFlag	false
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	operatingSegment
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CY2021Q3	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.glacierbancorp.com/20210930#PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.glacierbancorp.com/20210930#PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
CY2021Q3	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://www.glacierbancorp.com/20210930#PropertyPlantAndEquipmentAndLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
CY2021Q3	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherBorrowings
CY2020Q4	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherBorrowings
CY2020Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilities
CY2021Q3	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilities
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2021-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	000-18911
	dei	Entity Registrant Name EntityRegistrantName	GLACIER BANCORP, INC.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	MT
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	81-0519541
	dei	Entity Address Address Line1 EntityAddressAddressLine1	49 Commons Loop
	dei	Entity Address City Or Town EntityAddressCityOrTown	Kalispell,
	dei	Entity Address State Or Province EntityAddressStateOrProvince	MT
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	59901
	dei	City Area Code CityAreaCode	(406)
	dei	Local Phone Number LocalPhoneNumber	756-4200
	dei	Security12b Title Security12bTitle	Common Stock, $0.01 par value
	dei	Trading Symbol TradingSymbol	GBCI
	dei	Security Exchange Name SecurityExchangeName	NASDAQ
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
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CY2021Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	161888000	USD
CY2020Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	146217000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	479774000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	392691000	USD
CY2021Q3	gbci	Service Charges And Other Fees ServiceChargesAndOtherFees	15154000	USD
CY2020Q3	gbci	Service Charges And Other Fees ServiceChargesAndOtherFees	13404000	USD
	gbci	Service Charges And Other Fees ServiceChargesAndOtherFees	41741000	USD
	gbci	Service Charges And Other Fees ServiceChargesAndOtherFees	38790000	USD
CY2021Q3	gbci	Miscellaneous Loan Fees And Charges MiscellaneousLoanFeesAndCharges	2592000	USD
CY2020Q3	gbci	Miscellaneous Loan Fees And Charges MiscellaneousLoanFeesAndCharges	2084000	USD
	gbci	Miscellaneous Loan Fees And Charges MiscellaneousLoanFeesAndCharges	8293000	USD
	gbci	Miscellaneous Loan Fees And Charges MiscellaneousLoanFeesAndCharges	5051000	USD
CY2021Q3	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	13902000	USD
CY2020Q3	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	35516000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	51632000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	73236000	USD
CY2021Q3	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	-168000	USD
CY2020Q3	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	24000	USD
	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	55000	USD
	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	1015000	USD
CY2021Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	3335000	USD
CY2020Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2639000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	8737000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	10071000	USD
CY2021Q3	us-gaap	Noninterest Income NoninterestIncome	34815000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	53667000	USD
	us-gaap	Noninterest Income NoninterestIncome	110458000	USD
	us-gaap	Noninterest Income NoninterestIncome	128163000	USD
CY2021Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	66364000	USD
CY2020Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	64866000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	192941000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	182507000	USD
CY2021Q3	us-gaap	Occupancy Net OccupancyNet	9412000	USD
CY2020Q3	us-gaap	Occupancy Net OccupancyNet	9369000	USD
	us-gaap	Occupancy Net OccupancyNet	28135000	USD
	us-gaap	Occupancy Net OccupancyNet	27945000	USD
CY2021Q3	us-gaap	Advertising Expense AdvertisingExpense	3236000	USD
CY2020Q3	us-gaap	Advertising Expense AdvertisingExpense	2779000	USD
	us-gaap	Advertising Expense AdvertisingExpense	8513000	USD
	us-gaap	Advertising Expense AdvertisingExpense	7404000	USD
CY2021Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	5135000	USD
CY2020Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	5597000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	16002000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	15921000	USD
CY2021Q3	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	142000	USD
CY2020Q3	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	186000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	202000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	373000	USD
CY2021Q3	gbci	General Insurance And Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceAndFederalDepositInsuranceCorporationPremiumExpense	2011000	USD
CY2020Q3	gbci	General Insurance And Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceAndFederalDepositInsuranceCorporationPremiumExpense	1495000	USD
	gbci	General Insurance And Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceAndFederalDepositInsuranceCorporationPremiumExpense	5592000	USD
	gbci	General Insurance And Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceAndFederalDepositInsuranceCorporationPremiumExpense	3622000	USD
CY2021Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2488000	USD
CY2020Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2612000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	7464000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	7758000	USD
CY2021Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15320000	USD
CY2020Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	16469000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	41926000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	48094000	USD
CY2021Q3	us-gaap	Noninterest Expense NoninterestExpense	104108000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	103373000	USD
	us-gaap	Noninterest Expense NoninterestExpense	300775000	USD
	us-gaap	Noninterest Expense NoninterestExpense	293624000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	92595000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	96511000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	289457000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	227230000	USD
CY2021Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	16976000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18754000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	55409000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	42690000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	75619000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	77757000	USD
	us-gaap	Net Income Loss NetIncomeLoss	234048000	USD
	us-gaap	Net Income Loss NetIncomeLoss	184540000	USD
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.79
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.81
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.45
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.95
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.79
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.81
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.45
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.95
CY2021Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.32
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.30
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.95
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.88
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	95510772	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	95411656	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	95494211	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	94704198	shares
CY2021Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	95586202	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	95442576	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	95573519	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	94747894	shares
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	75619000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	77757000	USD
	us-gaap	Net Income Loss NetIncomeLoss	234048000	USD
	us-gaap	Net Income Loss NetIncomeLoss	184540000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-15259000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	1693000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-84929000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	123262000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	498000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	24000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	870000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	1014000	USD
CY2021Q3	us-gaap	Oci Debt Securities Available For Sale Transfer To Held To Maturity Adjustment From Aoci For Amortization Of Gain Loss Before Tax OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax	1379000	USD
CY2020Q3	us-gaap	Oci Debt Securities Available For Sale Transfer To Held To Maturity Adjustment From Aoci For Amortization Of Gain Loss Before Tax OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax	0	USD
	us-gaap	Oci Debt Securities Available For Sale Transfer To Held To Maturity Adjustment From Aoci For Amortization Of Gain Loss Before Tax OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax	2237000	USD
	us-gaap	Oci Debt Securities Available For Sale Transfer To Held To Maturity Adjustment From Aoci For Amortization Of Gain Loss Before Tax OciDebtSecuritiesAvailableForSaleTransferToHeldToMaturityAdjustmentFromAociForAmortizationOfGainLossBeforeTax	0	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-4330000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	424000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-22246000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	30979000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-12806000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1245000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-65790000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	91269000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	30000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-76000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	479000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-532000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	7000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-20000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	120000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	-135000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	23000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-56000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	359000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-397000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-12783000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	1189000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-65431000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	90872000	USD
CY2021Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	62836000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	78946000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	168617000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	275412000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	2203715000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	77757000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	1189000	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.30
CY2020Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	28683000	USD
CY2020Q3	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	1111000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	2255089000	USD
CY2021Q2	us-gaap	Stockholders Equity StockholdersEquity	2353955000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	75619000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-12783000	USD
CY2021Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.32
CY2021Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	30626000	USD
CY2021Q3	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	1451000	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	2387616000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	1960733000	USD
	us-gaap	Net Income Loss NetIncomeLoss	184540000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	90872000	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.88
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	84134000	USD
	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	112133000	USD
	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	3292000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	2255089000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	2307041000	USD
	us-gaap	Net Income Loss NetIncomeLoss	234048000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-65431000	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.95
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	90929000	USD
	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	2887000	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	2387616000	USD
	us-gaap	Net Income Loss NetIncomeLoss	234048000	USD
	us-gaap	Net Income Loss NetIncomeLoss	184540000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	-4880000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	41300000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-32934000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-10830000	USD
	gbci	Accretion Amortization Of Discounts And Premiums Business Combinations AccretionAmortizationOfDiscountsAndPremiumsBusinessCombinations	1003000	USD
	gbci	Accretion Amortization Of Discounts And Premiums Business Combinations AccretionAmortizationOfDiscountsAndPremiumsBusinessCombinations	23369000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	1184305000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	1393224000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	1372592000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	1400697000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	51632000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	73236000	USD
	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	55000	USD
	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	1015000	USD
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	2027000	USD
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	2059000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	3440000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	2829000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	15593000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	15124000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	127000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	64000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	7464000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	7758000	USD
	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	9520000	USD
	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	8244000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	4201000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	33558000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	5430000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	22729000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-868000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-861000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-3753000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-7450000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	417310000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	113757000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1026010000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	545191000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	4035869000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1839308000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	25480000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	29530000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	125527000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	0	USD
	us-gaap	Proceeds From Loan And Lease Originations And Principal Collections1 ProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections1	4825177000	USD
	us-gaap	Proceeds From Loan And Lease Originations And Principal Collections1 ProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections1	2978796000	USD
	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	5062750000	USD
	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	4627653000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	4187000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	8140000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	3246000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	2140000	USD
	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	180000	USD
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	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	7975000	USD
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	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	0	USD
	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	30000000	USD
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	0	USD
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	31271000	USD
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	us-gaap	Financing Receivable Allowance For Credit Losses Policy For Uncollectible Amounts FinancingReceivableAllowanceForCreditLossesPolicyForUncollectibleAmounts	<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Allowance for Credit Losses - Loans Receivable</span></div><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%">The allowance for credit losses for loans receivable represents management’s estimate of credit losses over the expected contractual life of the loan portfolio. The estimate is determined based on the amortized cost of the loan portfolio including the loan balance adjusted for charge-offs, recoveries, deferred fees and costs, and loan discount and premiums. Recoveries are included only to the extent that such amounts were previously charged-off. The Company has elected to exclude accrued interest from the estimate of credit losses for loans. Determining the adequacy of the allowance is complex and requires a high degree of judgment by management about the effect of matters that are inherently uncertain. Subsequent evaluations of the then-existing loan portfolio, in light of the factors then prevailing, may result in significant changes in the allowance in those future periods.</span></div><div><span><br/></span></div><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%">The allowance is increased for estimated credit losses which are recorded as expense. The portion of loans and overdraft balances determined by management to be uncollectable are charged-off as a reduction to the allowance and recoveries of amounts previously charged-off increase the allowance. The Company’s charge-off policy is consistent with bank regulatory standards. Consumer loans generally are charged-off when the loan becomes over 120 days delinquent. Real estate acquired as a result of foreclosure or by deed-in-lieu of foreclosure is classified as other real estate owned (“OREO”) until such time as it is sold. </span></div><div><span><br/></span></div><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%">The expected credit loss estimate process involves procedures to consider the unique characteristics of each of the Company’s loan portfolio segments, which consist of residential real estate, commercial real estate, other commercial, home equity, and other consumer loans. When computing the allowance levels, credit loss assumptions are estimated using a model that categorizes loan pools based on loss history, credit and risk characteristics, including current conditions and reasonable and supportable forecasts about the future. The Company has determined a four consecutive quarter forecasting period is a reasonable and supportable period. Expected credit loss for periods beyond reasonable and supportable forecast periods are determined based on a reversion method which reverts back to historical loss estimate over a four consecutive quarter period on a straight-line basis.</span></div><div style="text-align:justify"><span><br/></span></div><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%">Credit quality is assessed and monitored by evaluating various attributes and the results of those evaluations are utilized in underwriting new loans and the process for estimating the expected credit losses. The following paragraphs describe the risk characteristics relevant to each portfolio segment.</span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Residential Real Estate.</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> Residential real estate loans are secured by owner-occupied 1-4 family residences. Repayment of these loans is primarily dependent on the personal income and credit rating of the borrowers. Credit risk in these loans is impacted by economic conditions within the Company’s market areas that affect the value of the residential property securing the loans and affect the borrowers' personal incomes. Mitigating risk factors for this loan segment include a large number of borrowers, geographic dispersion of market areas and the loans are originated for relatively smaller amounts.</span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Commercial Real Estate</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">. Commercial real estate loans typically involve larger principal amounts, and repayment of these loans is generally dependent on the successful operation of the property securing the loan and/or the business conducted on the property securing the loan. Credit risk in these loans is impacted by the creditworthiness of a borrower, valuation of the property securing the loan and conditions within the local economies in the Company’s diverse, geographic market areas.</span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Commercial</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">. Commercial loans consist of loans to commercial customers for use in financing working capital needs, equipment purchases and business expansions. The loans in this category are repaid primarily from the cash flow of a </span></div><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%">borrower’s principal business operation. Credit risk in these loans is driven by creditworthiness of a borrower and the economic conditions that impact the cash flow stability from business operations across the Company’s diverse, geographic market areas.</span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Home Equity</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">. Home equity loans consist of junior lien mortgages and first and junior lien lines of credit (revolving open-end and amortizing closed-end) secured by owner-occupied 1-4 family residences. Repayment of these loans is primarily dependent on the personal income and credit rating of the borrowers. Credit risk in these loans is impacted by economic conditions within the Company’s market areas that affect the value of the residential property securing the loans and affect the borrowers' personal incomes. Mitigating risk factors for this loan segment are a large number of borrowers, geographic dispersion of market areas and the loans are originated for terms that range from 10 to 15 years.</span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Other Consumer</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">. The other consumer loan portfolio consists of various short-term loans such as automobile loans and loans for other personal purposes. Repayment of these loans is primarily dependent on the personal income of the borrowers. Credit risk is driven by consumer economic factors (such as unemployment and general economic conditions in the Company’s diverse, geographic market area) and the creditworthiness of a borrower. </span></div><div><span><br/></span></div><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%">The allowance is impacted by loan volumes, delinquency status, credit ratings, historical loss experiences, estimated prepayment speeds, weighted average lives and other conditions influencing loss expectations, such as reasonable and supportable forecasts of economic conditions. The methodology for estimating the amount of expected credit losses reported in the allowance has two basic components: 1) individual loans that do not share similar risk characteristics with other loans and the measurement of expected credit losses for such individual loans; and 2) the expected credit losses for pools of loans that share similar risk characteristics.</span></div><div><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Loans that do not Share Similar Risk Characteristics with Other Loans. </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For a loan that does not share similar risk characteristics with other loans, expected credit loss is measured based on the net realizable value, that is, the difference between the discounted value of the expected future cash flows, based on the original effective interest rate, and the amortized cost basis of the loan. For these loans, the expected credit loss is equal to the amount by which the net realizable value of the loan is less than the amortized cost basis of the loan (which is net of previous charge-offs and deferred loan fees and costs), except when the loan is collateral-dependent, that is, when foreclosure is probable or the borrower is experiencing financial difficulty and repayment is expected to be provided substantially through the operation or sale of the collateral. In these cases, expected credit loss is measured as the difference between the amortized cost basis of the loan and the fair value of the collateral. The fair value of the collateral is adjusted for the estimated cost to sell if repayment or satisfaction of a loan is dependent on the sale (rather than only on the operation) of the collateral. The Company has determined that non-accrual loans do not share similar risk characteristics with other loans and these loans are individually evaluated for estimated allowance for credit losses. The Company, through its credit monitoring process, may also identify other loans that do not share similar risk characteristics and individually evaluate such loans. The starting point for determining the fair value of collateral is to obtain external appraisals or evaluations (new or updated). The valuation techniques used in preparing appraisals or evaluations (new or updated) include the cost approach, income approach, sales comparison approach, or a combination of the preceding valuation techniques. The Company’s credit department reviews appraisals, giving consideration to the highest and best use of the collateral. The appraisals or evaluations (new or updated) are reviewed at least quarterly and more frequently based on current market conditions, including deterioration in a borrower’s financial condition and when property values may be subject to significant volatility. Adjustments may be made to the fair value of the collateral after review and acceptance of the collateral appraisal or evaluation (new or updated).</span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Loans that Share Similar Risk Characteristics with other Loans. </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For estimating the allowance for loans that share similar risk characteristics with other loans, such loans are segregated into loan segments. Loans are designated into loan segments based on loans pooled by product types and similar risk characteristics or areas of risk concentration. In determining the ACL, the Company derives an estimated credit loss assumption from a model that categorizes loan pools based on loan type which is further segregated by the credit quality indicators. This model calculates an expected loss percentage for each loan segment by considering the non-discounted simple annual average historical loss rate of each loan segment (calculated through an “open pool” method), multiplying the loss rate by the amortized loan balance and incorporating that segment’s internally generated prepayment speed assumption and contractually scheduled remaining principal pay downs on a loan level basis. The annual historical loss rates are adjusted over a reasonable economic forecast period by a multiplier that is calculated based upon current national economic forecasts as a proportion of each segment’s historical average loss levels. The Company will then revert from the economic forecast period back to the historical average loss rate in a straight-line basis. After the reversion period, the loans will be assumed to experience their historical loss rate for the remainder of their contractual lives. The model applies the expected loss rate over the projected cash flows at the individual loan level and then aggregates the losses by loan segment in determining their quantitative allowance. The Company will also include qualitative adjustments to adjust the ACL on loan </span></div><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%">segments</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> to the extent the current or future market conditions are believed to vary substantially from historical conditions in regards to:</span></div><div style="margin-top:6pt;padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">lending policies and procedures;</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">i</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">nternational, national, regional and local economic business conditions and developments that affect the collectability of the portfolio, including the condition of various markets;</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the nature and volume of the loan portfolio including the terms of the loans;</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the experience, ability, and depth of the lending management and other relevant staff;</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the volume and severity of past due and adversely classified or graded loans and the volume of non-accrual loans;</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the quality of our loan review system;</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the value of underlying collateral for collateralized loans;</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the existence and effect of any concentrations of credit, and changes in the level of concentrations; and</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the effect of external factors such as competition and legal and regulatory requirements on the level of estimated credit losses in the existing portfolio. </span></div><div><span><br/></span></div><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%">The Company regularly reviews loans in the portfolio to assess credit quality indicators and to determine the appropriate loan classification and grading in accordance with applicable bank regulations. The primary credit quality indicator for residential, home equity and other consumer loans is the days past due status, which consists of the following categories: 1) performing loans; 2) 30 to 89 days past due loans; and 3) non-accrual and ninety days or more past due loans. The primary credit quality indicator for commercial real estate and commercial loans is the Company’s internal risk rating system, which includes the following categories: 1) pass loans; 2) special mention loans; 3) substandard loans; and 4) doubtful or loss loans. Such credit quality indicators are regularly monitored and incorporated into the Company’s allowance estimate. The following paragraphs further define the internal risk ratings for commercial real estate and commercial loans. </span></div><div><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Pass Loans.</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> These ratings represent loans that are of acceptable, good or excellent quality with very limited to no risk. Loans that do not have one of the following ratings are considered pass loans. </span></div><div><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Special Mention Loans.</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> These ratings represent loans that are designated as special mention per the regulatory definition. Special mention loans are currently protected but are potentially weak. The credit risk may be relatively minor yet constitute an undue and unwarranted risk in light of the circumstances surrounding a specific loan. The rating may be used to identify credit with potential weaknesses that if not corrected may weaken the loan to the point of inadequately protecting the Bank’s credit position. Examples include a lack of supervision, inadequate loan agreement, condition, or control of collateral, incomplete, or improper documentation, deviations from lending policy, and adverse trends in operations or economic conditions.</span></div><div><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Substandard Loans. </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> This rating represents loans that are inadequately protected by the current sound worth and paying capacity of the obligor or of the collateral pledged. A loan so classified must have a well-defined weakness that jeopardizes the liquidation of the debt. These loans are characterized by the distinct possibility that the Bank will sustain some loss if the deficiencies are not corrected. Loss potential, while existing in the aggregated amount of substandard loans, does not have to exist in an individual loan classified substandard.</span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Doubtful/Loss Loans. </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> A loan classified as doubtful has the characteristics that make collection in full, on the basis of currently existing facts, conditions, and values, highly improbable. The possibility of loss is extremely high, but because of pending factors, which may work to the advantage and strengthening of the loan, its classification as loss is deferred until its more exact status may be determined. Pending factors include proposed merger, acquisition, or liquidation procedures, capital injection, perfecting liens on additional collateral and refinancing plans. Loans are classified as loss when they are deemed to be not collectible and of such little value that continuance as an active asset of the Bank is not warranted. Loans classified as loss must be charged-off. Assignment of this classification does not mean that an asset has absolutely no recovery or salvage value, but that it is not practical or desirable to defer writing off a basically worthless asset, even though partial recovery may be attained in the future.</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Restructured Loans</span></div><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%">A restructured loan is considered a troubled debt restructuring (“TDR”) if the creditor, for economic or legal reasons related to the debtor’s financial difficulties, grants a concession to the debtor that it would not otherwise consider. The Company periodically enters into restructure agreements with borrowers whereby the loans were previously identified as TDRs. When such circumstances occur, the Company carefully evaluates the facts of the subsequent restructure to determine the appropriate accounting and under certain circumstances it may be acceptable not to account for the subsequently restructured loan as a TDR. When assessing whether a concession has been granted by the Company, any prior forgiveness on a cumulative basis is considered a continuing concession. The Company has made the following types of loan modifications, some of which were considered a TDR:</span></div><div style="margin-top:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">reduction of the stated interest rate for the remaining term of the debt;</span></div><div style="padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">extension of the maturity date(s) at a stated rate of interest lower than the current market rate for newly originated debt having similar risk characteristics; and</span></div><div style="padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">reduction of the face amount of the debt as stated in the debt agreements.</span></div><div style="text-align:justify"><span><br/></span></div><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%">The Company recognizes that while borrowers may experience deterioration in their financial condition, many continue to be creditworthy borrowers who have the willingness and capacity for debt repayment. In determining whether non-restructured or performing loans issued to a single or related party group of borrowers should continue to accrue interest when the borrower has other loans that are non-performing or are TDRs, the Company on a quarterly or more frequent basis performs an updated and comprehensive assessment of the willingness and capacity of the borrowers to timely and ultimately repay their total debt obligations, including contingent obligations. Such analysis takes into account current financial information about the borrowers and financially responsible guarantors, if any, including for example:</span></div><div style="margin-top:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">analysis of global, i.e., aggregate debt service for total debt obligations;</span></div><div style="padding-left:36pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">assessment of the value and security protection of collateral pledged using current market conditions and alternative market assumptions across a variety of potential future situations; and</span></div><div style="padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">•</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">loan structures and related covenants.</span></div><div style="padding-left:36pt"><span><br/></span></div><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%">On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) was signed into law which includes many provisions that impact the Company and its customers. The banking regulatory agencies have encouraged banks to work with borrowers who have been impacted by the coronavirus disease of 2019 (“COVID-19”) and the CARES Act, along with related regulatory guidance, allows banks to not designate certain modifications as TDRs that otherwise may have been classified as TDRs. In general, in order to qualify for such treatment, the modifications need to be short-term and made on a good faith basis in response to the COVID-19 pandemic to borrowers who were previously deemed current as outlined in the regulatory guidance. The Company has made such modifications to assist borrowers impacted by the COVID-19 pandemic. </span></div><div style="text-align:justify"><span><br/></span></div><div style="text-align:justify"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The allowance for credit losses on a TDR is measured using the same method as all other loans held for investment. For a TDR that is individually reviewed and not collateral-dependent, the value of the concession can only be measured using the discounted cash flow method. When the value of a </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">concession is measured using the discounted cash flow method, the ACL is determined by discounting the expected future cash flows at the original interest of the loan.</span></div><div style="text-align:justify"><span><br/></span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline">Allowance for Credit Losses - Off-Balance Sheet Credit Exposures</span></div><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%">The Company maintains a separate allowance for off-balance sheet credit exposures, including unfunded loan commitments, which is included in other liabilities on the Company’s statements of financial condition. The Company estimates the amount of expected losses by calculating a commitment usage factor over the contractual period for exposures and applying the loss factors used in the allowance for credit loss methodology to the results of the usage calculation to estimate the liability for credit losses related to unfunded commitments for each loan segment. No credit loss estimate is reported for off-balance sheet credit exposures that are unconditionally cancellable by the Bank or for unfunded amounts under such arrangements that may be drawn prior to the cancellation of the arrangement. </span></div><div style="text-align:justify"><span><br/></span></div><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%;text-decoration:underline">Provision for Credit Losses</span></div>The Company recognizes provision for credit losses on the allowance for off-balance sheet credit exposures (e.g., unfunded loan commitments) together with provision for credit losses on the loan portfolio in the income statement line item provision for credit losses.
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CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	2317000	USD
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	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	2135000	USD
CY2021Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	725000	USD
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	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	41300000	USD
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	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	45789000	USD
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CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	261936000	USD
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	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	1000	USD
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CY2021Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0	USD
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CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	783000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	753000	USD
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CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	146283000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	792000	USD
	gbci	Available For Sale Securities In Unrealized Loss Positions Severity Rate AvailableForSaleSecuritiesInUnrealizedLossPositionsSeverityRate	0.05
CY2021Q3	gbci	Number Of Credit Rating Categories Highest NumberOfCreditRatingCategoriesHighest	4	security
CY2021Q3	gbci	Interest Receivable Available For Sale Debt Securities InterestReceivableAvailableForSaleDebtSecurities	17791000	USD
CY2020Q4	gbci	Interest Receivable Available For Sale Debt Securities InterestReceivableAvailableForSaleDebtSecurities	20215000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	1128299000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	189836000	USD
CY2021Q3	gbci	Number Of Credit Rating Categories Highest NumberOfCreditRatingCategoriesHighest	4	security
CY2021Q3	gbci	Interest Receivable Held To Maturity Debt Securities InterestReceivableHeldToMaturityDebtSecurities	11664000	USD
CY2020Q4	gbci	Interest Receivable Held To Maturity Debt Securities InterestReceivableHeldToMaturityDebtSecurities	1728000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	11293891000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	11122696000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	153609000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	158243000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	11140282000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	10964453000	USD
CY2021Q3	gbci	Unamortized Loan Origination Costs Fees UnamortizedLoanOriginationCostsFees	-26325000	USD
CY2020Q4	gbci	Unamortized Loan Origination Costs Fees UnamortizedLoanOriginationCostsFees	-26709000	USD
CY2021Q3	gbci	Unamortized Discounts And Premiums On Loans UnamortizedDiscountsAndPremiumsOnLoans	-12458000	USD
CY2020Q4	gbci	Unamortized Discounts And Premiums On Loans UnamortizedDiscountsAndPremiumsOnLoans	-17091000	USD
CY2021Q3	gbci	Interest Receivable Financing Receivable InterestReceivableFinancingReceivable	50229000	USD
CY2020Q4	gbci	Interest Receivable Financing Receivable InterestReceivableFinancingReceivable	53538000	USD
CY2021Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	151448000	USD
CY2021Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	2313000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2620000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	2468000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	153609000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	162509000	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	2869000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2630000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1804000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	164552000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	158243000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-2921000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	8566000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	6853000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	153609000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	124490000	USD
	us-gaap	Financing Receivable Change In Method Credit Loss Expense Reversal FinancingReceivableChangeInMethodCreditLossExpenseReversal	3720000	USD
	us-gaap	Financing Receivable Allowance For Credit Loss Purchased With Credit Deterioration Increase FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease	49000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	39165000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	7865000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	4993000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	164552000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	11293891000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	11122696000	USD
	gbci	Financing Receivable Nonaccrual Interest Income Reversed FinancingReceivableNonaccrualInterestIncomeReversed	472000	USD
	gbci	Financing Receivable Nonaccrual Interest Income Reversed FinancingReceivableNonaccrualInterestIncomeReversed	628000	USD
CY2021Q3	gbci	Collateral Dependent Loans CollateralDependentLoans	69533000	USD
CY2020Q4	gbci	Collateral Dependent Loans CollateralDependentLoans	64455000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	0	Loan
CY2020Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	6	Loan
CY2020Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	7482000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	7482000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	Loan
CY2020Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	10	Loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	2368000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	2368000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	Loan
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	16	Loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	14945000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	14945000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	Loan
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
CY2021Q3	gbci	Tdr With Pre Modification Loan Balance For Which Oreo Was Received TDRWithPreModificationLoanBalanceForWhichOreoWasReceived	1624000	USD
CY2020Q3	gbci	Tdr With Pre Modification Loan Balance For Which Oreo Was Received TDRWithPreModificationLoanBalanceForWhichOreoWasReceived	2265000	USD
CY2021Q3	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	83000	USD
CY2020Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	548000	USD
CY2021Q3	gbci	Real Estate Acquired Through Foreclosure Securedby Residential Real Estate RealEstateAcquiredThroughForeclosureSecuredbyResidentialRealEstate	88000	USD
CY2020Q4	gbci	Real Estate Acquired Through Foreclosure Securedby Residential Real Estate RealEstateAcquiredThroughForeclosureSecuredbyResidentialRealEstate	273000	USD
CY2021Q3	us-gaap	Finance Lease Right Of Use Asset Before Accumulated Amortization FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization	5999000	USD
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset Before Accumulated Amortization FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization	5999000	USD
CY2021Q3	us-gaap	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	457000	USD
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	273000	USD
CY2021Q3	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	5542000	USD
CY2021Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	44480000	USD
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	5726000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	46820000	USD
CY2021Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	5810000	USD
CY2021Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	47590000	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	5891000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	49675000	USD
CY2021Q3	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P23Y
CY2021Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P17Y
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P24Y
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P17Y
CY2021Q3	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.026
CY2021Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.035
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.026
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.034
CY2021Q3	us-gaap	Finance Lease Liability Payments Due In Next Rolling Twelve Months FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths	66000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Next Rolling Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths	1219000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due In Rolling Year Two FinanceLeaseLiabilityPaymentsDueInRollingYearTwo	266000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Two LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo	4625000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due In Rolling Year Three FinanceLeaseLiabilityPaymentsDueInRollingYearThree	272000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Three LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree	3973000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due In Rolling Year Four FinanceLeaseLiabilityPaymentsDueInRollingYearFour	280000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Four LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour	3932000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due In Rolling Year Five FinanceLeaseLiabilityPaymentsDueInRollingYearFive	285000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Five LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive	3859000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due In Rolling After Year Five FinanceLeaseLiabilityPaymentsDueInRollingAfterYearFive	6736000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due After Rolling Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive	47447000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	7905000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	65055000	USD
CY2021Q3	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	28000	USD
CY2021Q3	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	1527000	USD
CY2021Q3	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	5782000	USD
CY2021Q3	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	46063000	USD
CY2021Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	5810000	USD
CY2021Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	47590000	USD
CY2021Q3	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	2095000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	17465000	USD
CY2021Q3	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	61000	USD
CY2020Q3	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	59000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	184000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	174000	USD
CY2021Q3	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	38000	USD
CY2020Q3	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	40000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	113000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	121000	USD
CY2021Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	1302000	USD
CY2020Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	1254000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	3883000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	3553000	USD
CY2021Q3	us-gaap	Short Term Lease Cost ShortTermLeaseCost	93000	USD
CY2020Q3	us-gaap	Short Term Lease Cost ShortTermLeaseCost	88000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	261000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	266000	USD
CY2021Q3	us-gaap	Variable Lease Cost VariableLeaseCost	264000	USD
CY2020Q3	us-gaap	Variable Lease Cost VariableLeaseCost	264000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	759000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	977000	USD
CY2021Q3	us-gaap	Sublease Income SubleaseIncome	11000	USD
CY2020Q3	us-gaap	Sublease Income SubleaseIncome	2000	USD
	us-gaap	Sublease Income SubleaseIncome	32000	USD
	us-gaap	Sublease Income SubleaseIncome	5000	USD
CY2021Q3	us-gaap	Lease Cost LeaseCost	1747000	USD
CY2020Q3	us-gaap	Lease Cost LeaseCost	1703000	USD
	us-gaap	Lease Cost LeaseCost	5168000	USD
	us-gaap	Lease Cost LeaseCost	5086000	USD
CY2021Q3	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	38000	USD
CY2021Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	813000	USD
CY2020Q3	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	40000	USD
CY2020Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	706000	USD
CY2021Q3	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	27000	USD
CY2020Q3	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	23000	USD
	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	113000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	2379000	USD
	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	121000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	1994000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	81000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	67000	USD
CY2021Q2	us-gaap	Goodwill Goodwill	514013000	USD
CY2020Q2	us-gaap	Goodwill Goodwill	513355000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	514013000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	456418000	USD
CY2021Q3	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
CY2020Q3	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	658000	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	57595000	USD
CY2021Q3	us-gaap	Goodwill Goodwill	514013000	USD
CY2020Q3	us-gaap	Goodwill Goodwill	514013000	USD
CY2021Q3	us-gaap	Goodwill Goodwill	514013000	USD
CY2020Q3	us-gaap	Goodwill Goodwill	514013000	USD
CY2020Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	40159000	USD
CY2021Q3	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	40159000	USD
CY2020Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	8976000	USD
CY2019Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	1618000	USD
	us-gaap	Servicing Asset At Amortized Value Additions ServicingAssetAtAmortizedValueAdditions	3996000	USD
	us-gaap	Servicing Asset At Amortized Value Additions ServicingAssetAtAmortizedValueAdditions	8298000	USD
	us-gaap	Servicing Asset At Amortized Value Amortization1 ServicingAssetAtAmortizedValueAmortization1	1327000	USD
	us-gaap	Servicing Asset At Amortized Value Amortization1 ServicingAssetAtAmortizedValueAmortization1	940000	USD
CY2021Q3	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	11645000	USD
CY2020Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	8976000	USD
CY2021Q3	us-gaap	Servicing Asset ServicingAsset	1511199000	USD
CY2020Q4	us-gaap	Servicing Asset ServicingAsset	1269080000	USD
CY2021Q3	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	15477000	USD
CY2020Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	12087000	USD
	us-gaap	Affordable Housing Project Investment Write Down Amount AffordableHousingProjectInvestmentWriteDownAmount	0	USD
	us-gaap	Affordable Housing Project Investment Write Down Amount AffordableHousingProjectInvestmentWriteDownAmount	0	USD
CY2021Q3	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	1604000	USD
CY2020Q3	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	1936000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	6330000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	5766000	USD
CY2021Q3	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	2983000	USD
CY2020Q3	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	2608000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	9260000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	7771000	USD
CY2021Q3	us-gaap	Pledged Financial Instruments Not Separately Reported Securities For Repurchase Agreements PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements	1197475000	USD
CY2020Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Securities For Repurchase Agreements PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements	1151264000	USD
CY2021Q3	gbci	Consulting Fees ConsultingFees	3003000	USD
CY2020Q3	gbci	Consulting Fees ConsultingFees	4050000	USD
	gbci	Consulting Fees ConsultingFees	7918000	USD
	gbci	Consulting Fees ConsultingFees	8604000	USD
CY2021Q3	gbci	Loan Related Expenses LoanRelatedExpenses	1649000	USD
CY2020Q3	gbci	Loan Related Expenses LoanRelatedExpenses	1743000	USD
	gbci	Loan Related Expenses LoanRelatedExpenses	5028000	USD
	gbci	Loan Related Expenses LoanRelatedExpenses	3732000	USD
CY2021Q3	gbci	Vie Write Downs Losses And Other Expenses VIEWriteDownsLossesAndOtherExpenses	1668000	USD
CY2020Q3	gbci	Vie Write Downs Losses And Other Expenses VIEWriteDownsLossesAndOtherExpenses	1510000	USD
	gbci	Vie Write Downs Losses And Other Expenses VIEWriteDownsLossesAndOtherExpenses	4342000	USD
	gbci	Vie Write Downs Losses And Other Expenses VIEWriteDownsLossesAndOtherExpenses	3396000	USD
CY2021Q3	gbci	Telephone Expenses TelephoneExpenses	1330000	USD
CY2020Q3	gbci	Telephone Expenses TelephoneExpenses	1314000	USD
	gbci	Telephone Expenses TelephoneExpenses	4044000	USD
	gbci	Telephone Expenses TelephoneExpenses	3865000	USD
CY2021Q3	gbci	Debit Card Expense DebitCardExpense	1469000	USD
CY2020Q3	gbci	Debit Card Expense DebitCardExpense	1414000	USD
	gbci	Debit Card Expense DebitCardExpense	3761000	USD
	gbci	Debit Card Expense DebitCardExpense	3704000	USD
CY2021Q3	us-gaap	Business Development BusinessDevelopment	1360000	USD
CY2020Q3	us-gaap	Business Development BusinessDevelopment	1139000	USD
	us-gaap	Business Development BusinessDevelopment	3230000	USD
	us-gaap	Business Development BusinessDevelopment	3110000	USD
CY2021Q3	us-gaap	Postage Expense PostageExpense	894000	USD
CY2020Q3	us-gaap	Postage Expense PostageExpense	851000	USD
	us-gaap	Postage Expense PostageExpense	2729000	USD
	us-gaap	Postage Expense PostageExpense	2479000	USD
CY2021Q3	us-gaap	Supplies Expense SuppliesExpense	840000	USD
CY2020Q3	us-gaap	Supplies Expense SuppliesExpense	877000	USD
	us-gaap	Supplies Expense SuppliesExpense	2453000	USD
	us-gaap	Supplies Expense SuppliesExpense	2704000	USD
CY2021Q3	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	953000	USD
CY2020Q3	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	560000	USD
	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	2137000	USD
	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	2247000	USD
CY2021Q3	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	472000	USD
CY2020Q3	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	792000	USD
	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	1654000	USD
	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	7311000	USD
CY2021Q3	us-gaap	Legal Fees LegalFees	283000	USD
CY2020Q3	us-gaap	Legal Fees LegalFees	206000	USD
	us-gaap	Legal Fees LegalFees	1075000	USD
	us-gaap	Legal Fees LegalFees	1025000	USD
CY2021Q3	gbci	Deposit Related Expenses DepositRelatedExpenses	307000	USD
CY2020Q3	gbci	Deposit Related Expenses DepositRelatedExpenses	355000	USD
	gbci	Deposit Related Expenses DepositRelatedExpenses	1061000	USD
	gbci	Deposit Related Expenses DepositRelatedExpenses	1263000	USD
CY2021Q3	gbci	Accounting Fees AccountingFees	172000	USD
CY2020Q3	gbci	Accounting Fees AccountingFees	455000	USD
	gbci	Accounting Fees AccountingFees	865000	USD
	gbci	Accounting Fees AccountingFees	1453000	USD
CY2021Q3	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	65000	USD
CY2020Q3	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	0	USD
	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	1463000	USD
	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-125000	USD
CY2021Q3	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	985000	USD
CY2020Q3	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	1203000	USD
	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	3092000	USD
	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	3076000	USD
CY2021Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15320000	USD
CY2020Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	16469000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	41926000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	48094000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	91630000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	758000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	90872000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-63109000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-65431000	USD
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	75619000	USD
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	75619000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	77757000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	77757000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	234048000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	234048000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	184540000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	184540000	USD
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	95510772	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	95411656	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	95494211	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	94704198	shares
CY2021Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	75430	shares
CY2020Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	30920	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	79308	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	43696	shares
CY2021Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	95586202	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	95442576	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	95573519	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	94747894	shares
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.79
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.81
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.45
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.95
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.79
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.81
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.45
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.95
CY2021Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2020Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	93253	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	78605	shares

Files In Submission

Name	View Source	Status
0000868671-21-000089-index-headers.html	Edgar Link	pending
0000868671-21-000089-index.html	Edgar Link	pending
0000868671-21-000089.txt	Edgar Link	pending
0000868671-21-000089-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
gbci-09302021xex311.htm	Edgar Link	pending
gbci-09302021xex312.htm	Edgar Link	pending
gbci-09302021xex32.htm	Edgar Link	pending
gbci-20210930.htm	Edgar Link	pending
gbci-20210930.xsd	Edgar Link	pending
gbci-20210930_cal.xml	Edgar Link	unprocessable
gbci-20210930_def.xml	Edgar Link	unprocessable
gbci-20210930_htm.xml	Edgar Link	completed
gbci-20210930_lab.xml	Edgar Link	unprocessable
gbci-20210930_pre.xml	Edgar Link	unprocessable
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
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report.css	Edgar Link	pending
Show.js	Edgar Link	pending

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$GBCI
GLACIER BANCORP, INC. Stock $gbci

2021 Q4 Form 10-Q Financial Statement

#000086867121000089 Filed on November 01, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$GBCI GLACIER BANCORP, INC. Stock $gbci

2021 Q4 Form 10-Q Financial Statement

#000086867121000089 Filed on November 01, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$GBCI
GLACIER BANCORP, INC. Stock $gbci