$GBCI
GLACIER BANCORP, INC. Stock $gbci

$gbci Overview Financials Valuation SEC Filings Company Website

2020 Q2 Form 10-Q Financial Statement

#000086867120000072 Filed on July 31, 2020

Income Statement

Concept	2020 Q2	2019 Q2	2019 Q1
Revenue	$155.4M	$132.4M	$126.1M
YoY Change	17.39%	12.46%	22.36%
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	$7.700M	$6.300M	$6.300M
YoY Change	22.22%	14.55%	31.25%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$7.185M	$12.09M	$10.90M
YoY Change	-40.57%	31.96%	40.26%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$77.75M	$64.96M	$60.80M
YoY Change	19.69%	20.59%	29.48%
Income Tax	$14.31M	$12.57M	$11.67M
% Of Pretax Income	18.4%	19.35%	19.19%
Net Earnings	$63.44M	$52.39M	$49.13M
YoY Change	21.09%	18.04%	27.42%
Net Earnings / Revenue	40.83%	39.58%	38.96%
Basic Earnings Per Share	$0.67	$0.61	$0.58
Diluted Earnings Per Share	$0.66	$0.61	$0.58
COMMON SHARES
Basic Shares Outstanding	95.41M shares	85.83M shares	84.55M shares
Diluted Shares Outstanding	95.43M shares	85.86M shares	84.61M shares

Balance Sheet

Concept	2020 Q2	2019 Q2	2019 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$547.6M	$231.2M	$202.5M
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	$326.0M	$296.9M	$277.6M
YoY Change	9.8%	23.52%	16.41%
Goodwill	$513.4M	$330.9M	$289.6M
YoY Change	55.15%	14.28%	0.02%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$0.00	$3.000M	$13.00M
YoY Change	-100.0%	-91.18%	-60.61%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$16.91B	$12.68B	$12.07B
YoY Change	33.37%	6.55%	3.56%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$4.000M	$5.000M	$5.000M
YoY Change	-20.0%	25.0%	25.0%
Accrued Expenses	$48.00M	$44.00M	$38.00M
YoY Change	9.09%
Deferred Revenue
YoY Change
Short-Term Debt	$881.0M	$495.0M	$490.0M
YoY Change	77.98%	36.74%	23.74%
Long-Term Debt Due	$0.00	$0.00	$0.00
YoY Change
Total Short-Term Liabilities	$52.00M	$49.00M	$43.00M
YoY Change	6.12%	1125.0%	975.0%
LONG-TERM LIABILITIES
Long-Term Debt	$172.0M	$155.0M	$149.0M
YoY Change	10.97%	7.64%	4.93%
Other Long-Term Liabilities	$153.0M	$116.0M	$99.00M
YoY Change	31.9%	20.83%	11.24%
Total Long-Term Liabilities	$325.0M	$271.0M	$248.0M
YoY Change	19.93%	12.92%	7.36%
TOTAL LIABILITIES
Total Short-Term Liabilities	$52.00M	$49.00M	$43.00M
Total Long-Term Liabilities	$325.0M	$271.0M	$248.0M
Total Liabilities	$14.70B	$10.99B	$10.52B
YoY Change	33.8%	5.42%	3.12%
SHAREHOLDERS EQUITY
Retained Earnings	$580.0M	$503.8M	$474.8M
YoY Change	15.14%	13.54%	12.69%
Common Stock	$1.493B	$1.139B	$1.051B
YoY Change	31.03%	8.53%	0.23%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$2.204B	$1.687B	$1.551B
YoY Change
Total Liabilities & Shareholders Equity	$16.91B	$12.68B	$12.07B
YoY Change	33.37%	6.55%	3.56%

Cashflow Statement

Concept	2020 Q2	2019 Q2	2019 Q1
OPERATING ACTIVITIES
Net Income	$63.44M	$52.39M	$49.13M
YoY Change	21.09%	18.04%	27.42%
Depreciation, Depletion And Amortization	$7.700M	$6.300M	$6.300M
YoY Change	22.22%	14.55%	31.25%
Cash From Operating Activities	$111.4M	$39.40M	$46.31M
YoY Change	182.74%	-23.2%	-3.4%
INVESTING ACTIVITIES
Capital Expenditures	-$4.000M	-$8.100M	-$3.800M
YoY Change	-50.62%	42.11%	-32.14%
Acquisitions			$0.00
YoY Change			-100.0%
Other Investing Activities	-$1.455B	-$141.3M	$81.00M
YoY Change	930.01%	-55.95%	-175.91%
Cash From Investing Activities	-$1.459B	-$149.3M	$77.21M
YoY Change	877.49%	-54.27%	-168.76%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	1.622B	138.7M	-$124.8M
YoY Change	1069.57%	-27.84%	-139.56%
NET CHANGE
Cash From Operating Activities	111.4M	39.40M	$46.31M
Cash From Investing Activities	-1.459B	-149.3M	$77.21M
Cash From Financing Activities	1.622B	138.7M	-$124.8M
Net Change In Cash	274.2M	28.80M	-$1.263M
YoY Change	852.08%	-134.7%	-100.5%
FREE CASH FLOW
Cash From Operating Activities	$111.4M	$39.40M	$46.31M
Capital Expenditures	-$4.000M	-$8.100M	-$3.800M
Free Cash Flow	$115.4M	$47.50M	$50.11M
YoY Change	142.95%	-16.67%	-6.41%

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	2020
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q2
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
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CY2020Q2	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2019Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
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	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	operating_segment
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CY2020Q2	gbci	Debt Securities Available For Sale Past Due DebtSecuritiesAvailableForSalePastDue	0	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Past Due DebtSecuritiesHeldToMaturityPastDue	0	USD
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	us-gaap	Affordable Housing Project Investment Write Down Amount AffordableHousingProjectInvestmentWriteDownAmount	0	USD
	us-gaap	Affordable Housing Project Investment Write Down Amount AffordableHousingProjectInvestmentWriteDownAmount	0	USD
	gbci	Fair Value Measurement Transfers From One Level To Another FairValueMeasurementTransfersFromOneLevelToAnother	0	USD
	gbci	Fair Value Measurement Transfers From One Level To Another FairValueMeasurementTransfersFromOneLevelToAnother	0	USD
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-06-30
	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
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	gbci	Miscellaneous Loan Feesand Charges MiscellaneousLoanFeesandCharges	2967000	USD
	gbci	Miscellaneous Loan Feesand Charges MiscellaneousLoanFeesandCharges	2159000	USD
CY2020Q2	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	25858000	USD
CY2019Q2	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	7762000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	37720000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	13560000	USD
CY2020Q2	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	128000	USD
CY2019Q2	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	134000	USD
	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	991000	USD
	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	347000	USD
CY2020Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2190000	USD
CY2019Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	1721000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	7432000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	5202000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	41224000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	30834000	USD
	us-gaap	Noninterest Income NoninterestIncome	74496000	USD
	us-gaap	Noninterest Income NoninterestIncome	59308000	USD
CY2020Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	57981000	USD
CY2019Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	51973000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	117641000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	104701000	USD
CY2020Q2	us-gaap	Occupancy Net OccupancyNet	9357000	USD
CY2019Q2	us-gaap	Occupancy Net OccupancyNet	8180000	USD
	us-gaap	Occupancy Net OccupancyNet	18576000	USD
	us-gaap	Occupancy Net OccupancyNet	16617000	USD
CY2020Q2	us-gaap	Advertising Expense AdvertisingExpense	2138000	USD
CY2019Q2	us-gaap	Advertising Expense AdvertisingExpense	2767000	USD
	us-gaap	Advertising Expense AdvertisingExpense	4625000	USD
	us-gaap	Advertising Expense AdvertisingExpense	5155000	USD
CY2020Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	5042000	USD
CY2019Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	4062000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	10324000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	7954000	USD
CY2020Q2	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	75000	USD
CY2019Q2	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	191000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	187000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	330000	USD
CY2020Q2	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	1037000	USD
CY2019Q2	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	1848000	USD
	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	2127000	USD
	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	3133000	USD
CY2020Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2613000	USD
CY2019Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1865000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5146000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3559000	USD
CY2020Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	19898000	USD
CY2019Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15284000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	31443000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	27551000	USD
CY2020Q2	us-gaap	Noninterest Expense NoninterestExpense	98141000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	86170000	USD
	us-gaap	Noninterest Expense NoninterestExpense	190069000	USD
	us-gaap	Noninterest Expense NoninterestExpense	169000000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	77750000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	64960000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	130719000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	125759000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	14306000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	12568000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	23936000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	24235000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	63444000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	52392000	USD
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	85191658	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	95430403	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	85858286	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	94395930	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	85241238	shares
	us-gaap	Net Income Loss NetIncomeLoss	106783000	USD
	us-gaap	Net Income Loss NetIncomeLoss	106783000	USD
	us-gaap	Net Income Loss NetIncomeLoss	101524000	USD
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.67
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.61
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.13
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.66
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.61
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.13
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.19
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.29
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.27
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.58
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.53
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	95405493	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	85826290	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	94346582	shares
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	63444000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	52392000	USD
	us-gaap	Net Income Loss NetIncomeLoss	101524000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	41014000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	29877000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	121569000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	76329000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	128000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	134000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	990000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	355000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	40886000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	29743000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	120579000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	75974000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	10360000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	7537000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	30555000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	19252000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-115000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-897000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	30526000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	22206000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	90024000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	56722000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-456000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-3820000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-456000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-5654000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	0	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-278000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	0	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-501000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	-456000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	-3542000	USD
	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	-456000	USD
	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	-5153000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-115000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-1306000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-341000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-2645000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-341000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-3847000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	30185000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	19561000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	89683000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	52875000	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	93629000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	71953000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	196466000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	154399000	USD
CY2019Q1	us-gaap	Stockholders Equity StockholdersEquity	1550850000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	52392000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	19561000	USD
CY2019Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	23437000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	87153000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
CY2019Q2	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	857000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	1687376000	USD
CY2020Q1	us-gaap	Stockholders Equity StockholdersEquity	2136644000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	63444000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	30185000	USD
CY2020Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	27724000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
CY2020Q2	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	1166000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	2203715000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	1515854000	USD
	us-gaap	Net Income Loss NetIncomeLoss	101524000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	52875000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	45476000	USD
	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	87153000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	904000	USD
CY2019Q2	us-gaap	Cumulative Effect Of New Accounting Principle In Period Of Adoption CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	-25458000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	1687376000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	1960733000	USD
	us-gaap	Net Income Loss NetIncomeLoss	106783000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	89683000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	55451000	USD
	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	112133000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	2181000	USD
CY2020Q2	us-gaap	Cumulative Effect Of New Accounting Principle In Period Of Adoption CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	-12347000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	2203715000	USD
	us-gaap	Net Income Loss NetIncomeLoss	106783000	USD
	us-gaap	Net Income Loss NetIncomeLoss	101524000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	36296000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	57000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-6831000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-8707000	USD
	gbci	Accretion Amortizationof Discountsand Premiums Business Combinations AccretionAmortizationofDiscountsandPremiumsBusinessCombinations	-33329000	USD
	gbci	Accretion Amortizationof Discountsand Premiums Business Combinations AccretionAmortizationofDiscountsandPremiumsBusinessCombinations	2187000	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	0	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	825000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	847288000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	353921000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	849626000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	346144000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	37720000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	13560000	USD
	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	991000	USD
	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	347000	USD
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	1356000	USD
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	1021000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	1994000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	1850000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	9907000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	9011000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	169000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	334000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5146000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3559000	USD
	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	4973000	USD
	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	3885000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	19529000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	3213000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	15048000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	6520000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-602000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	749000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	4992000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-9518000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	137174000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	85690000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	415093000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	341724000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	247854000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1042423000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	457915000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	20250000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	32575000	USD
	us-gaap	Proceeds From Loan And Lease Originations And Principal Collections1 ProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections1	1835968000	USD
	us-gaap	Proceeds From Loan And Lease Originations And Principal Collections1 ProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections1	1364270000	USD
	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	3371733000	USD
	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	1675181000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	4861000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	11882000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	1523000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	2440000	USD
	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	75049000	USD
	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	76948000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	71398000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	71198000	USD
	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	7321000	USD
	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	6451000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-43713000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-11307000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-2179509000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-72140000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	2001950000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	86429000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	304154000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	97091000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	-30000000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	-120000000	USD
	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	30000000	USD
	us-gaap	Proceeds From Federal Home Loan Bank Borrowings ProceedsFromFederalHomeLoanBankBorrowings	0	USD
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	631000	USD
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	987000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	43000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	54000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	46324000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	47560000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1003000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1158000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	795000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	0	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	2258984000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	13869000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	216649000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	27419000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	330961000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	203790000	USD
CY2020Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	547610000	USD
CY2019Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	231209000	USD
	us-gaap	Interest Paid Net InterestPaidNet	16282000	USD
	us-gaap	Interest Paid Net InterestPaidNet	22244000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	8550000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	21680000	USD
	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	215000	USD
	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	7000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	791000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	1914000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	5253000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3862000	USD
	gbci	Dividends Declared But Not Paid Duringthe Period DividendsDeclaredButNotPaidDuringthePeriod	27785000	USD
	gbci	Dividends Declared But Not Paid Duringthe Period DividendsDeclaredButNotPaidDuringthePeriod	23482000	USD
	us-gaap	Stock Issued1 StockIssued1	112133000	USD
	us-gaap	Stock Issued1 StockIssued1	87153000	USD
	gbci	Cash Considerationfor Outstanding Shares CashConsiderationforOutstandingShares	13721000	USD
	gbci	Cash Considerationfor Outstanding Shares CashConsiderationforOutstandingShares	4000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	744109000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	379155000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	618255000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	291998000	USD
CY2020Q2	gbci	Number Of Bank Divisions NumberOfBankDivisions	16	division
	gbci	Financing Receivable Allowance For Credit Losses Forecasting Period FinancingReceivableAllowanceForCreditLossesForecastingPeriod	4	quarter
	gbci	Financing Receivable Allowance For Credit Losses Forecasting Period FinancingReceivableAllowanceForCreditLossesForecastingPeriod	4	quarter
	gbci	Financing Receivable Allowance For Credit Losses Number Of Components FinancingReceivableAllowanceForCreditLossesNumberOfComponents	2	numberOfComponents
	gbci	Period Of Finance Receivable Modifications Due To Covid19 PeriodOfFinanceReceivableModificationsDueToCOVID19	P6M
	gbci	Maximum Term Leases Will Be Considered Shortterm MaximumTermLeasesWillBeConsideredShortterm	P12M
	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	26239000	USD
	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	38943000	USD
CY2020Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	114672000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3359493000	USD
CY2020Q2	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	175026000	USD
CY2020Q2	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	569000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3533950000	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	203275000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	12608000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2020Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	215883000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2521374000	USD
CY2019Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	55965000	USD
CY2019Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	2087000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2575252000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	224611000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	9785000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	234396000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	144070000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	145977000	USD
CY2020Q2	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	0	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	0	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	269452000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	281526000	USD
CY2020Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	17132000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	18339000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	261463000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	275179000	USD
CY2020Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	71471000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	76970000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	950305000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	1016343000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	120574000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	1625290000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	1719025000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	203275000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	215883000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3359493000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3533950000	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	203275000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	215883000	USD
CY2020Q2	gbci	Proceedsfrom Salesand Callsof Debt Securities Availableforsale ProceedsfromSalesandCallsofDebtSecuritiesAvailableforsale	37711000	USD
CY2019Q2	gbci	Proceedsfrom Salesand Callsof Debt Securities Availableforsale ProceedsfromSalesandCallsofDebtSecuritiesAvailableforsale	172323000	USD
	gbci	Proceedsfrom Salesand Callsof Debt Securities Availableforsale ProceedsfromSalesandCallsofDebtSecuritiesAvailableforsale	114784000	USD
	gbci	Proceedsfrom Salesand Callsof Debt Securities Availableforsale ProceedsfromSalesandCallsofDebtSecuritiesAvailableforsale	476371000	USD
CY2020Q2	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	142000	USD
CY2019Q2	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	1347000	USD
	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	1104000	USD
	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	4284000	USD
CY2020Q2	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	14000	USD
CY2019Q2	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	1213000	USD
	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	114000	USD
	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	3929000	USD
CY2020Q2	gbci	Heldto Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldtoMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	0	USD
CY2019Q2	gbci	Heldto Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldtoMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	2630000	USD
	gbci	Heldto Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldtoMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	20250000	USD
	gbci	Heldto Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldtoMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	32575000	USD
CY2020Q2	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	0	USD
CY2019Q2	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	0	USD
	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	1000	USD
	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	2000	USD
CY2020Q2	gbci	Heldto Maturity Securities Sold Security Realized Loss HeldtoMaturitySecuritiesSoldSecurityRealizedLoss	0	USD
CY2019Q2	gbci	Heldto Maturity Securities Sold Security Realized Loss HeldtoMaturitySecuritiesSoldSecurityRealizedLoss	0	USD
	gbci	Heldto Maturity Securities Sold Security Realized Loss HeldtoMaturitySecuritiesSoldSecurityRealizedLoss	0	USD
	gbci	Heldto Maturity Securities Sold Security Realized Loss HeldtoMaturitySecuritiesSoldSecurityRealizedLoss	10000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	64	security
CY2020Q2	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	63864000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	560000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	765000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	9000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	64629000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	569000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	88	security
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	289499000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1608000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	46637000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	479000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	336136000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	2087000	USD
	gbci	Available For Sale Securities In Unrealized Loss Positions Severity Rate AvailableForSaleSecuritiesInUnrealizedLossPositionsSeverityRate	0.05
CY2020Q2	gbci	Number Of Credit Rating Categories Highest NumberOfCreditRatingCategoriesHighest	4	security
CY2020Q2	gbci	Interest Receivable Available For Sale Debt Securities InterestReceivableAvailableForSaleDebtSecurities	18970000	USD
	us-gaap	Debt Securities Available For Sale Purchased With Credit Deterioration Amount At Par Value DebtSecuritiesAvailableForSalePurchasedWithCreditDeteriorationAmountAtParValue	0	USD
	us-gaap	Debt Securities Available For Sale Purchased With Credit Deterioration Allowance For Credit Loss At Acquisition Date DebtSecuritiesAvailableForSalePurchasedWithCreditDeteriorationAllowanceForCreditLossAtAcquisitionDate	0	USD
CY2019Q4	gbci	Unamortized Loan Origination Feesand Costs UnamortizedLoanOriginationFeesandCosts	-6964000	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	203275000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	224611000	USD
CY2020Q2	gbci	Number Of Credit Rating Categories Highest NumberOfCreditRatingCategoriesHighest	4	security
CY2020Q2	gbci	Interest Receivable Held To Maturity Debt Securities InterestReceivableHeldToMaturityDebtSecurities	1956000	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	11453378000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	9512810000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	162509000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	124490000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	11290869000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	9388320000	USD
CY2020Q2	gbci	Unamortized Loan Origination Feesand Costs UnamortizedLoanOriginationFeesandCosts	-41811000	USD
CY2020Q2	gbci	Unamortized Discountsand Premiumson Loans UnamortizedDiscountsandPremiumsonLoans	-18954000	USD
CY2019Q4	gbci	Unamortized Discountsand Premiumson Loans UnamortizedDiscountsandPremiumsonLoans	-21574000	USD
CY2020Q2	gbci	Interest Receivable Financing Receivable InterestReceivableFinancingReceivable	56415000	USD
CY2019Q4	gbci	Interest Receivable Financing Receivable InterestReceivableFinancingReceivable	40962000	USD
CY2020Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	150190000	USD
CY2020Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	13552000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2668000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1435000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	162509000	USD
CY2019Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	129786000	USD
CY2019Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2859000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	2127000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	129054000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	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	36296000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	5235000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	3189000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	162509000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	131239000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	57000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	6200000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	3958000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	129054000	USD
	us-gaap	Financing Receivable Purchased With Credit Deterioration Amount At Par Value FinancingReceivablePurchasedWithCreditDeteriorationAmountAtParValue	3401000	USD
	us-gaap	Financing Receivable Purchased With Credit Deterioration Allowance For Credit Loss At Acquisition Date FinancingReceivablePurchasedWithCreditDeteriorationAllowanceForCreditLossAtAcquisitionDate	49000	USD
	us-gaap	Financing Receivable Purchased With Credit Deterioration Discount Premium FinancingReceivablePurchasedWithCreditDeteriorationDiscountPremium	13000	USD
CY2020Q2	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	30578000	USD
CY2020Q2	gbci	Financing Receivable Nonaccrual With Allowance FinancingReceivableNonaccrualWithAllowance	4579000	USD
CY2020Q2	gbci	Financing Receivable Recorded Investment Past Due And Non Accrual Loans FinancingReceivableRecordedInvestmentPastDueAndNonAccrualLoans	66453000	USD
CY2020Q2	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	11386925000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	11453378000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	30883000	USD
CY2019Q4	gbci	Financing Receivable Recorded Investment Past Due And Non Accrual Loans FinancingReceivableRecordedInvestmentPastDueAndNonAccrualLoans	55487000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	9457323000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	9512810000	USD
	gbci	Financing Receivable Nonaccrual Interest Income Reversed FinancingReceivableNonaccrualInterestIncomeReversed	517000	USD
CY2020Q2	gbci	Collateral Dependent Loans CollateralDependentLoans	24041000	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	8	Loan
CY2020Q2	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	1672000	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	1672000	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	Loan
CY2020Q2	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	4	Loan
CY2019Q2	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	388000	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	374000	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	Loan
CY2019Q2	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	305000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	13	Loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	8940000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	8940000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	Loan
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	106000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	8	Loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	2093000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	2079000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	Loan
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	305000	USD
CY2020Q2	gbci	Tdr With Pre Modification Loan Balance For Which Oreo Was Received TdrWithPreModificationLoanBalanceForWhichOreoWasReceived	904000	USD
CY2019Q2	gbci	Tdr With Pre Modification Loan Balance For Which Oreo Was Received TdrWithPreModificationLoanBalanceForWhichOreoWasReceived	2528000	USD
CY2020Q2	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	1001000	USD
CY2019Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	1744000	USD
CY2020Q2	gbci	Real Estate Acquired Through Foreclosure Securedby Residential Real Estate RealEstateAcquiredThroughForeclosureSecuredbyResidentialRealEstate	1896000	USD
CY2019Q4	gbci	Real Estate Acquired Through Foreclosure Securedby Residential Real Estate RealEstateAcquiredThroughForeclosureSecuredbyResidentialRealEstate	1504000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	94504000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	9418306000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	9512810000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	95000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	124395000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	124490000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	5388000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	5388000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	95000	USD
CY2019	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	10378000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	89116000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	99355000	USD
CY2019	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	93338000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	94504000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	104743000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	95000	USD
CY2019	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	103716000	USD
CY2020Q2	gbci	Finance Lease Right Of Use Asset Gross FinanceLeaseRightOfUseAssetGross	5618000	USD
CY2019Q4	gbci	Finance Lease Right Of Use Asset Gross FinanceLeaseRightOfUseAssetGross	6537000	USD
CY2020Q2	gbci	Finance Lease Rightof Use Asset Accumulated Amortization FinanceLeaseRightofUseAssetAccumulatedAmortization	153000	USD
CY2019Q4	gbci	Finance Lease Rightof Use Asset Accumulated Amortization FinanceLeaseRightofUseAssetAccumulatedAmortization	917000	USD
CY2020Q2	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	5465000	USD
CY2020Q2	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	45131000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	5620000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	41453000	USD
CY2020Q2	us-gaap	Finance Lease Liability FinanceLeaseLiability	5559000	USD
CY2020Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	47807000	USD
CY2019Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	5671000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	43904000	USD
CY2020Q2	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P24Y
CY2020Q2	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P18Y
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P24Y
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P19Y
CY2020Q2	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.029
CY2020Q2	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.036
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.030
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.037
CY2020Q2	us-gaap	Finance Lease Liability Payments Due In Next Rolling Twelve Months FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths	251000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Next Rolling Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths	4388000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due In Rolling Year Two FinanceLeaseLiabilityPaymentsDueInRollingYearTwo	258000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Two LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo	4272000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due In Rolling Year Three FinanceLeaseLiabilityPaymentsDueInRollingYearThree	264000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Three LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree	3808000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due In Rolling Year Four FinanceLeaseLiabilityPaymentsDueInRollingYearFour	270000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Four LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour	3507000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due In Rolling Year Five FinanceLeaseLiabilityPaymentsDueInRollingYearFive	277000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Five LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive	3453000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due After Rolling Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive	47744000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due In Rolling After Year Five FinanceLeaseLiabilityPaymentsDueInRollingAfterYearFive	6658000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	7978000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	67172000	USD
CY2020Q2	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	92000	USD
CY2020Q2	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	2755000	USD
CY2020Q2	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	5467000	USD
CY2020Q2	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	45052000	USD
CY2020Q2	us-gaap	Finance Lease Liability FinanceLeaseLiability	5559000	USD
CY2020Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	47807000	USD
CY2020Q2	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	2419000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	19365000	USD
CY2020Q2	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	58000	USD
CY2019Q2	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	16000	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	41301000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	115000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	32000	USD
CY2020Q2	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	40000	USD
CY2019Q2	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	2000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	81000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	4000	USD
CY2020Q2	us-gaap	Operating Lease Cost OperatingLeaseCost	1191000	USD
CY2019Q2	us-gaap	Operating Lease Cost OperatingLeaseCost	997000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	2299000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	1910000	USD
CY2020Q2	us-gaap	Short Term Lease Cost ShortTermLeaseCost	88000	USD
CY2019Q2	us-gaap	Short Term Lease Cost ShortTermLeaseCost	119000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	178000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	228000	USD
CY2020Q2	us-gaap	Variable Lease Cost VariableLeaseCost	328000	USD
CY2019Q2	us-gaap	Variable Lease Cost VariableLeaseCost	222000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	713000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	421000	USD
CY2020Q2	us-gaap	Sublease Income SubleaseIncome	1000	USD
CY2019Q2	us-gaap	Sublease Income SubleaseIncome	1000	USD
	us-gaap	Sublease Income SubleaseIncome	3000	USD
	us-gaap	Sublease Income SubleaseIncome	3000	USD
CY2020Q2	us-gaap	Lease Cost LeaseCost	1704000	USD
CY2019Q2	us-gaap	Lease Cost LeaseCost	1355000	USD
	us-gaap	Lease Cost LeaseCost	3383000	USD
	us-gaap	Lease Cost LeaseCost	2592000	USD
CY2020Q2	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	40000	USD
CY2020Q2	us-gaap	Operating Lease Payments OperatingLeasePayments	673000	USD
CY2019Q2	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	2000	USD
CY2019Q2	us-gaap	Operating Lease Payments OperatingLeasePayments	497000	USD
CY2020Q2	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	21000	USD
CY2019Q2	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	21000	USD
	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	81000	USD
	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	2401000	USD
CY2020Q2	us-gaap	Postage Expense PostageExpense	833000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	1288000	USD
	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	4000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	976000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	44000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	42000	USD
CY2020Q1	us-gaap	Goodwill Goodwill	513355000	USD
CY2019Q1	us-gaap	Goodwill Goodwill	289586000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	456418000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	289586000	USD
CY2020Q2	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
CY2019Q2	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	41301000	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	56937000	USD
CY2020Q2	us-gaap	Goodwill Goodwill	513355000	USD
CY2019Q2	us-gaap	Goodwill Goodwill	330887000	USD
CY2020Q2	us-gaap	Goodwill Goodwill	513355000	USD
CY2019Q2	us-gaap	Goodwill Goodwill	330887000	USD
CY2020Q2	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	1988000	USD
CY2019Q2	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	1478000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	3830000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	2895000	USD
CY2020Q2	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	2678000	USD
CY2019Q2	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	2009000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	5163000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	3967000	USD
CY2020Q2	us-gaap	Pledged Financial Instruments Not Separately Reported Securities For Repurchase Agreements PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements	976567000	USD
CY2019Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Securities For Repurchase Agreements PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements	711210000	USD
CY2020Q2	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	3728000	USD
CY2019Q2	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	1831000	USD
	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	6519000	USD
	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	2045000	USD
CY2020Q2	gbci	Consulting Fees ConsultingFees	2319000	USD
CY2019Q2	gbci	Consulting Fees ConsultingFees	2010000	USD
	gbci	Consulting Fees ConsultingFees	4554000	USD
	gbci	Consulting Fees ConsultingFees	3777000	USD
CY2020Q2	gbci	Telephone Expenses TelephoneExpenses	1313000	USD
CY2019Q2	gbci	Telephone Expenses TelephoneExpenses	1210000	USD
	gbci	Telephone Expenses TelephoneExpenses	2551000	USD
	gbci	Telephone Expenses TelephoneExpenses	2385000	USD
CY2020Q2	gbci	Debit Card Expense DebitCardExpense	1197000	USD
CY2019Q2	gbci	Debit Card Expense DebitCardExpense	1435000	USD
	gbci	Debit Card Expense DebitCardExpense	2290000	USD
	gbci	Debit Card Expense DebitCardExpense	3304000	USD
CY2020Q2	us-gaap	Business Development BusinessDevelopment	923000	USD
CY2019Q2	us-gaap	Business Development BusinessDevelopment	1123000	USD
	us-gaap	Business Development BusinessDevelopment	1971000	USD
	us-gaap	Business Development BusinessDevelopment	2013000	USD
CY2020Q2	gbci	Vie Writedowns Lossesand Other Expenses VIEWritedownsLossesandOtherExpenses	1045000	USD
CY2019Q2	gbci	Vie Writedowns Lossesand Other Expenses VIEWritedownsLossesandOtherExpenses	906000	USD
	gbci	Vie Writedowns Lossesand Other Expenses VIEWritedownsLossesandOtherExpenses	1886000	USD
	gbci	Vie Writedowns Lossesand Other Expenses VIEWritedownsLossesandOtherExpenses	1451000	USD
CY2020Q2	us-gaap	Supplies Expense SuppliesExpense	924000	USD
CY2019Q2	us-gaap	Supplies Expense SuppliesExpense	786000	USD
	us-gaap	Supplies Expense SuppliesExpense	1827000	USD
	us-gaap	Supplies Expense SuppliesExpense	1511000	USD
CY2020Q2	gbci	Loan Related Expenses LoanRelatedExpenses	4502000	USD
CY2019Q2	gbci	Loan Related Expenses LoanRelatedExpenses	943000	USD
	gbci	Loan Related Expenses LoanRelatedExpenses	1807000	USD
	gbci	Loan Related Expenses LoanRelatedExpenses	1802000	USD
CY2020Q2	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	644000	USD
CY2019Q2	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	1405000	USD
	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	1687000	USD
CY2019Q2	us-gaap	Postage Expense PostageExpense	823000	USD
	us-gaap	Postage Expense PostageExpense	1628000	USD
	us-gaap	Postage Expense PostageExpense	1656000	USD
CY2020Q2	gbci	Accounting Fees AccountingFees	550000	USD
CY2019Q2	gbci	Accounting Fees AccountingFees	472000	USD
	gbci	Accounting Fees AccountingFees	998000	USD
	gbci	Accounting Fees AccountingFees	925000	USD
CY2020Q2	gbci	Deposit Related Expenses DepositRelatedExpenses	551000	USD
CY2019Q2	gbci	Deposit Related Expenses DepositRelatedExpenses	630000	USD
	gbci	Deposit Related Expenses DepositRelatedExpenses	908000	USD
	gbci	Deposit Related Expenses DepositRelatedExpenses	992000	USD
CY2020Q2	us-gaap	Legal Fees LegalFees	386000	USD
CY2019Q2	us-gaap	Legal Fees LegalFees	281000	USD
	us-gaap	Legal Fees LegalFees	819000	USD
	us-gaap	Legal Fees LegalFees	588000	USD
CY2020Q2	gbci	Atm Expenses ATMExpenses	28000	USD
CY2019Q2	gbci	Atm Expenses ATMExpenses	519000	USD
	gbci	Atm Expenses ATMExpenses	128000	USD
	gbci	Atm Expenses ATMExpenses	1013000	USD
CY2020Q2	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	955000	USD
CY2019Q2	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	910000	USD
	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	1870000	USD
	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	1688000	USD
CY2020Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	19898000	USD
CY2019Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15284000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	31443000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	27551000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-9427000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	52766000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-109000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	52875000	USD
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	43448000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	40226000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	90422000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	739000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	89683000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	129909000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	63444000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	52392000	USD
	us-gaap	Net Income Loss NetIncomeLoss	106783000	USD
	us-gaap	Net Income Loss NetIncomeLoss	101524000	USD
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	95405493	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	85826290	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	94346582	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	85191658	shares
CY2020Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	24910	shares
CY2019Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	31996	shares
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	10324000	USD
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	49348	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	49580	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	95430403	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	85858286	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	94395930	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	85241238	shares
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.67
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.61
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.13
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.66
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.61
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.13
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.19
CY2020Q2	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	143938	shares
CY2019Q2	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	121533	shares
	us-gaap	Occupancy Net OccupancyNet	18576000	USD
	us-gaap	Advertising Expense AdvertisingExpense	4625000	USD
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
	gbci	Service Chargesand Other Fees ServiceChargesandOtherFees	25386000	USD
	gbci	Miscellaneous Loan Feesand Charges MiscellaneousLoanFeesandCharges	2967000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	37720000	USD
	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	991000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	7432000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	117641000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	187000	USD
	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	2127000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5146000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	31443000	USD

Files In Submission

Name	View Source	Status
0000868671-20-000072-index-headers.html	Edgar Link	pending
0000868671-20-000072-index.html	Edgar Link	pending
0000868671-20-000072.txt	Edgar Link	pending
0000868671-20-000072-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
gbci-06302020xex311.htm	Edgar Link	pending
gbci-06302020xex312.htm	Edgar Link	pending
gbci-06302020xex32.htm	Edgar Link	pending
gbci-20200630.htm	Edgar Link	pending
gbci-20200630.xsd	Edgar Link	pending
gbci-20200630_cal.xml	Edgar Link	unprocessable
gbci-20200630_def.xml	Edgar Link	unprocessable
gbci-20200630_htm.xml	Edgar Link	completed
gbci-20200630_lab.xml	Edgar Link	unprocessable
gbci-20200630_pre.xml	Edgar Link	unprocessable
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
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R8.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending

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$GBCI
GLACIER BANCORP, INC. Stock $gbci

2020 Q2 Form 10-Q Financial Statement

#000086867120000072 Filed on July 31, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$GBCI GLACIER BANCORP, INC. Stock $gbci

2020 Q2 Form 10-Q Financial Statement

#000086867120000072 Filed on July 31, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$GBCI
GLACIER BANCORP, INC. Stock $gbci