$GBCI
GLACIER BANCORP, INC. Stock $gbci

$gbci Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-Q Financial Statement

#000086867119000055 Filed on November 04, 2019

Income Statement

Concept	2019 Q4	2019 Q3	2018 Q3
Revenue	$145.3M	$142.4M	$122.9M
YoY Change	15.94%	15.86%	27.41%
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	$7.500M	$7.000M	$5.700M
YoY Change	19.05%	22.81%	29.55%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$8.833M	$10.95M	$9.160M
YoY Change	-6.39%	19.51%	19.71%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$69.61M	$63.82M	$60.14M
YoY Change	13.66%	6.13%	24.98%
Income Tax	$12.20M	$12.21M	$10.80M
% Of Pretax Income	17.53%	19.13%	17.96%
Net Earnings	$57.41M	$51.61M	$49.34M
YoY Change	15.75%	4.61%	35.24%
Net Earnings / Revenue	39.52%	36.24%	40.14%
Basic Earnings Per Share	$0.62	$0.57	$0.58
Diluted Earnings Per Share	$0.62	$0.57	$0.58
COMMON SHARES
Basic Shares Outstanding	92.19M shares	90.29M shares	84.52M shares
Diluted Shares Outstanding		90.45M shares	84.59M shares

Balance Sheet

Concept	2019 Q4	2019 Q3	2018 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$331.0M	$406.4M	$307.1M
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	$263.2M	$307.6M	$239.0M
YoY Change	8.99%	28.7%	33.77%
Goodwill	$456.4M	$456.4M	$289.5M
YoY Change	57.61%	57.64%	62.83%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$2.000M	$0.00	$37.00M
YoY Change	-91.67%	-100.0%	-37.29%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$13.68B	$13.72B	$11.91B
YoY Change	12.95%	15.2%	21.54%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$5.000M	$4.000M	$4.000M
YoY Change	25.0%	0.0%	33.33%
Accrued Expenses	$44.00M	$44.00M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$570.0M	$559.0M	$409.0M
YoY Change	43.94%	36.67%	-9.91%
Long-Term Debt Due	$0.00	$0.00
YoY Change
Total Short-Term Liabilities	$49.00M	$48.00M	$4.000M
YoY Change	1125.0%	1100.0%	33.33%
LONG-TERM LIABILITIES
Long-Term Debt	$169.0M	$155.0M	$144.0M
YoY Change	13.42%	7.64%	7.46%
Other Long-Term Liabilities	$121.0M	$126.0M	$103.0M
YoY Change	3.42%	22.33%	28.75%
Total Long-Term Liabilities	$290.0M	$281.0M	$247.0M
YoY Change	9.02%	13.77%	15.42%
TOTAL LIABILITIES
Total Short-Term Liabilities	$49.00M	$48.00M	$4.000M
Total Long-Term Liabilities	$290.0M	$281.0M	$247.0M
Total Liabilities	$11.72B	$11.77B	$10.42B
YoY Change	10.6%	12.95%	21.23%
SHAREHOLDERS EQUITY
Retained Earnings	$541.1M	$528.6M	$471.0M
YoY Change	14.34%	12.22%	16.77%
Common Stock	$1.379B	$1.376B	$1.050B
YoY Change	31.13%	30.97%	31.74%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$1.961B	$1.953B	$1.493B
YoY Change
Total Liabilities & Shareholders Equity	$13.68B	$13.72B	$11.91B
YoY Change	12.95%	15.2%	21.54%

Cashflow Statement

Concept	2019 Q4	2019 Q3	2018 Q3
OPERATING ACTIVITIES
Net Income	$57.41M	$51.61M	$49.34M
YoY Change	15.75%	4.61%	35.24%
Depreciation, Depletion And Amortization	$7.500M	$7.000M	$5.700M
YoY Change	19.05%	22.81%	29.55%
Cash From Operating Activities	$112.2M	$28.70M	$68.30M
YoY Change	-0.88%	-57.98%	63.4%
INVESTING ACTIVITIES
Capital Expenditures	-$2.200M	-$2.300M	-$2.700M
YoY Change	-52.17%	-14.81%	8.0%
Acquisitions
YoY Change
Other Investing Activities	-$96.70M	$130.7M	-$89.20M
YoY Change	-71.31%	-246.52%	-207.08%
Cash From Investing Activities	-$98.90M	$128.3M	-$91.90M
YoY Change	-71.06%	-239.61%	-213.74%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-88.80M	18.10M	-37.30M
YoY Change	-170.93%	-148.53%	-73.36%
NET CHANGE
Cash From Operating Activities	112.2M	28.70M	68.30M
Cash From Investing Activities	-98.90M	128.3M	-91.90M
Cash From Financing Activities	-88.80M	18.10M	-37.30M
Net Change In Cash	-75.50M	175.1M	-60.90M
YoY Change	-26.91%	-387.52%	250.0%
FREE CASH FLOW
Cash From Operating Activities	$112.2M	$28.70M	$68.30M
Capital Expenditures	-$2.200M	-$2.300M	-$2.700M
Free Cash Flow	$114.4M	$31.00M	$71.00M
YoY Change	-2.89%	-56.34%	60.27%

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	2019
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2019Q3	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2018Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2019Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	1000000	shares
CY2018Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	1000000	shares
CY2019Q3	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2018Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2019Q3	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2018Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2019Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2018Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2019Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	117187500	shares
CY2018Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	117187500	shares
	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	operating_segment
CY2019Q3	us-gaap	Capitalized Contract Cost Accumulated Impairment CapitalizedContractCostAccumulatedImpairment	0	USD
CY2018Q4	us-gaap	Capitalized Contract Cost Accumulated Impairment CapitalizedContractCostAccumulatedImpairment	0	USD
	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2018	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2019Q3	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	40159000	USD
CY2018Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	40159000	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
	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	2019-09-30
	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
CY2019Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	92187453	shares
CY2019Q3	us-gaap	Cash And Due From Banks CashAndDueFromBanks	233623000	USD
CY2018Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	161782000	USD
CY2019Q3	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	172761000	USD
CY2018Q4	us-gaap	Interest Bearing Deposits In Banks InterestBearingDepositsInBanks	42008000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents And Federal Funds Sold CashCashEquivalentsAndFederalFundsSold	406384000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents And Federal Funds Sold CashCashEquivalentsAndFederalFundsSold	203790000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2459036000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2571663000	USD
CY2019Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	234992000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	297915000	USD
CY2019Q3	us-gaap	Debt Securities DebtSecurities	2694028000	USD
CY2018Q4	us-gaap	Debt Securities DebtSecurities	2869578000	USD
CY2019Q3	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	100441000	USD
CY2018Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	33156000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	9541088000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	8287549000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	125535000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	131239000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	9415553000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	8156310000	USD
CY2019Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	307590000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	241528000	USD
CY2019Q3	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	7148000	USD
CY2018Q4	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	7480000	USD
CY2019Q3	us-gaap	Interest Receivable InterestReceivable	63294000	USD
CY2018Q4	us-gaap	Interest Receivable InterestReceivable	54408000	USD
CY2019Q3	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	0	USD
CY2018Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	23564000	USD
CY2019Q3	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	65852000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	49242000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	456422000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	289586000	USD
CY2019Q3	gbci	Nonmarketable Securities Equity Securities NonmarketableSecuritiesEquitySecurities	10427000	USD
CY2018Q4	gbci	Nonmarketable Securities Equity Securities NonmarketableSecuritiesEquitySecurities	27871000	USD
CY2019Q3	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	108814000	USD
CY2018Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	82320000	USD
CY2019Q3	us-gaap	Other Assets OtherAssets	82839000	USD
CY2018Q4	us-gaap	Other Assets OtherAssets	76651000	USD
CY2019Q3	us-gaap	Assets Assets	13718792000	USD
CY2018Q4	us-gaap	Assets Assets	12115484000	USD
CY2019Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	3772766000	USD
CY2018Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	3001178000	USD
CY2019Q3	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	7095859000	USD
CY2018Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	6492589000	USD
CY2019Q3	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	558752000	USD
CY2018Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	396151000	USD
CY2019Q3	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	8707000	USD
CY2018Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	440175000	USD
CY2019Q3	us-gaap	Other Borrowings OtherBorrowings	14808000	USD
CY2018Q4	us-gaap	Other Borrowings OtherBorrowings	14708000	USD
CY2019Q3	us-gaap	Subordinated Debt SubordinatedDebt	139913000	USD
CY2018Q4	us-gaap	Subordinated Debt SubordinatedDebt	134051000	USD
CY2019Q3	us-gaap	Interest Payable Current And Noncurrent InterestPayableCurrentAndNoncurrent	4435000	USD
CY2018Q4	us-gaap	Interest Payable Current And Noncurrent InterestPayableCurrentAndNoncurrent	4252000	USD
CY2019Q3	us-gaap	Other Liabilities OtherLiabilities	170151000	USD
CY2018Q4	us-gaap	Other Liabilities OtherLiabilities	116526000	USD
CY2019Q3	us-gaap	Liabilities Liabilities	11765391000	USD
CY2018Q4	us-gaap	Liabilities Liabilities	10599630000	USD
CY2019Q3	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2018Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2019Q3	us-gaap	Common Stock Value Outstanding CommonStockValueOutstanding	922000	USD
CY2018Q4	us-gaap	Common Stock Value Outstanding CommonStockValueOutstanding	845000	USD
CY2019Q3	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	1375785000	USD
CY2018Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	1051253000	USD
CY2019Q3	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	528599000	USD
CY2018Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	473183000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	48095000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-9427000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	1953401000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	1515854000	USD
CY2019Q3	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	13718792000	USD
CY2018Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	12115484000	USD
CY2019Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	92180618	shares
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	84521692	shares
CY2019Q3	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	21357000	USD
CY2018Q3	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	21971000	USD
	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	64600000	USD
	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	64483000	USD
CY2019Q3	us-gaap	Interest And Fee Income Loans Consumer Real Estate InterestAndFeeIncomeLoansConsumerRealEstate	12156000	USD
CY2018Q3	us-gaap	Interest And Fee Income Loans Consumer Real Estate InterestAndFeeIncomeLoansConsumerRealEstate	10356000	USD
	us-gaap	Interest And Fee Income Loans Consumer Real Estate InterestAndFeeIncomeLoansConsumerRealEstate	34345000	USD
	us-gaap	Interest And Fee Income Loans Consumer Real Estate InterestAndFeeIncomeLoansConsumerRealEstate	29290000	USD
CY2019Q3	us-gaap	Interest And Fee Income Loans Commercial InterestAndFeeIncomeLoansCommercial	97224000	USD
CY2018Q3	us-gaap	Interest And Fee Income Loans Commercial InterestAndFeeIncomeLoansCommercial	80587000	USD
	us-gaap	Interest And Fee Income Loans Commercial InterestAndFeeIncomeLoansCommercial	268806000	USD
	us-gaap	Interest And Fee Income Loans Commercial InterestAndFeeIncomeLoansCommercial	221926000	USD
CY2019Q3	us-gaap	Interest And Fee Income Loans Other Consumer InterestAndFeeIncomeLoansOtherConsumer	11658000	USD
CY2018Q3	us-gaap	Interest And Fee Income Loans Other Consumer InterestAndFeeIncomeLoansOtherConsumer	9991000	USD
	us-gaap	Interest And Fee Income Loans Other Consumer InterestAndFeeIncomeLoansOtherConsumer	33145000	USD
	us-gaap	Interest And Fee Income Loans Other Consumer InterestAndFeeIncomeLoansOtherConsumer	27987000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	142395000	USD
CY2018Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	122905000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	400896000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	343686000	USD
CY2019Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	6214000	USD
CY2018Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	4837000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	17179000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	13370000	USD
CY2019Q3	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	999000	USD
CY2018Q3	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	570000	USD
	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	2687000	USD
	us-gaap	Interest Expense Securities Sold Under Agreements To Repurchase InterestExpenseSecuritiesSoldUnderAgreementsToRepurchase	1541000	USD
CY2019Q3	gbci	Interest Expense Federal Home Loan Bank Advance InterestExpenseFederalHomeLoanBankAdvance	2035000	USD
CY2018Q3	gbci	Interest Expense Federal Home Loan Bank Advance InterestExpenseFederalHomeLoanBankAdvance	2132000	USD
	gbci	Interest Expense Federal Home Loan Bank Advance InterestExpenseFederalHomeLoanBankAdvance	8937000	USD
	gbci	Interest Expense Federal Home Loan Bank Advance InterestExpenseFederalHomeLoanBankAdvance	6734000	USD
CY2019Q3	us-gaap	Interest Expense Other InterestExpenseOther	47000	USD
CY2018Q3	us-gaap	Interest Expense Other InterestExpenseOther	63000	USD
	us-gaap	Interest Expense Other InterestExpenseOther	123000	USD
	us-gaap	Interest Expense Other InterestExpenseOther	105000	USD
CY2019Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	1652000	USD
CY2018Q3	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	1558000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	5014000	USD
	us-gaap	Interest Expense Junior Subordinated Debentures InterestExpenseJuniorSubordinatedDebentures	4345000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	10947000	USD
CY2018Q3	us-gaap	Interest Expense InterestExpense	9160000	USD
	us-gaap	Interest Expense InterestExpense	33940000	USD
	us-gaap	Interest Expense InterestExpense	26095000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	131448000	USD
	us-gaap	Noninterest Income NoninterestIncome	102357000	USD
	us-gaap	Noninterest Income NoninterestIncome	90330000	USD
CY2019Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	62509000	USD
CY2018Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	49927000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	167210000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	144671000	USD
CY2019Q3	us-gaap	Occupancy Net OccupancyNet	8731000	USD
CY2018Q3	us-gaap	Occupancy Net OccupancyNet	7914000	USD
	us-gaap	Occupancy Net OccupancyNet	25348000	USD
CY2018Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	113745000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	366956000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	317591000	USD
CY2019Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	0	USD
CY2018Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	3194000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	57000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	8707000	USD
CY2019Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	131448000	USD
CY2018Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	110551000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	366899000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	308884000	USD
CY2019Q3	gbci	Service Chargesand Other Fees ServiceChargesandOtherFees	15138000	USD
CY2018Q3	gbci	Service Chargesand Other Fees ServiceChargesandOtherFees	19504000	USD
	gbci	Service Chargesand Other Fees ServiceChargesandOtherFees	53178000	USD
	gbci	Service Chargesand Other Fees ServiceChargesandOtherFees	55179000	USD
CY2019Q3	gbci	Miscellaneous Loan Feesand Charges MiscellaneousLoanFeesandCharges	1775000	USD
	us-gaap	Occupancy Net OccupancyNet	22850000	USD
CY2019Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	4466000	USD
CY2018Q3	gbci	Miscellaneous Loan Feesand Charges MiscellaneousLoanFeesandCharges	1807000	USD
	gbci	Miscellaneous Loan Feesand Charges MiscellaneousLoanFeesandCharges	3934000	USD
	gbci	Miscellaneous Loan Feesand Charges MiscellaneousLoanFeesandCharges	5527000	USD
CY2019Q3	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	10369000	USD
CY2018Q3	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	7256000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	23929000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	21495000	USD
CY2019Q3	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	13811000	USD
CY2018Q3	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	-367000	USD
	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	14158000	USD
	us-gaap	Debt Securities Realized Gain Loss DebtSecuritiesRealizedGainLoss	-756000	USD
CY2019Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	1956000	USD
CY2018Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	4216000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	7158000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	8885000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	43049000	USD
CY2018Q3	us-gaap	Noninterest Income NoninterestIncome	32416000	USD
CY2019Q3	us-gaap	Advertising Expense AdvertisingExpense	2719000	USD
CY2018Q3	us-gaap	Advertising Expense AdvertisingExpense	2432000	USD
	us-gaap	Advertising Expense AdvertisingExpense	7874000	USD
	us-gaap	Advertising Expense AdvertisingExpense	7132000	USD
CY2018Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	3752000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	12420000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	11960000	USD
CY2019Q3	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	166000	USD
CY2018Q3	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	2674000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	496000	USD
	us-gaap	Foreclosed Real Estate Expense ForeclosedRealEstateExpense	2957000	USD
CY2019Q3	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	593000	USD
CY2018Q3	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	1277000	USD
	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	3726000	USD
	gbci	General Insuranceand Federal Deposit Insurance Corporation Premium Expense GeneralInsuranceandFederalDepositInsuranceCorporationPremiumExpense	3812000	USD
CY2019Q3	gbci	Loss On Hedging Activity LossOnHedgingActivity	13528000	USD
CY2018Q3	gbci	Loss On Hedging Activity LossOnHedgingActivity	0	USD
	gbci	Loss On Hedging Activity LossOnHedgingActivity	13528000	USD
	gbci	Loss On Hedging Activity LossOnHedgingActivity	0	USD
CY2019Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2360000	USD
CY2018Q3	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1735000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	36447000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5919000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4539000	USD
CY2019Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15603000	USD
CY2018Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	13118000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	43154000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	40330000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	110675000	USD
CY2018Q3	us-gaap	Noninterest Expense NoninterestExpense	82829000	USD
	us-gaap	Noninterest Expense NoninterestExpense	279675000	USD
	us-gaap	Noninterest Expense NoninterestExpense	238251000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	63822000	USD
CY2018Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	60138000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	189581000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	160963000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	12212000	USD
CY2018Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10802000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	28684000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	51610000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	49336000	USD
	us-gaap	Net Income Loss NetIncomeLoss	153134000	USD
	us-gaap	Net Income Loss NetIncomeLoss	132279000	USD
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.57
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.58
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.76
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.59
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.57
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.58
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.76
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.59
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.29
CY2018Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.26
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.82
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.75
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	90294811	shares
CY2018Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	84518407	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	86911402	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	83294111	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	90449195	shares
CY2018Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	84593122	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87082178	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	83362323	shares
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	51610000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	49336000	USD
	us-gaap	Net Income Loss NetIncomeLoss	153134000	USD
	us-gaap	Net Income Loss NetIncomeLoss	132279000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	11113000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-14190000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	87442000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-46597000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	13811000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	151000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	14166000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-195000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-2698000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-14341000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	73276000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-46402000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-684000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-3634000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	18568000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-11759000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-2014000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-10707000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	54708000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-34643000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-1393000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	1234000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-7047000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	7302000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-10315000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-469000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-10816000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-1946000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	8922000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	1703000	USD
	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	3769000	USD
	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Before Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesBeforeTax	9248000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	2261000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	431000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	955000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	2343000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	6661000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	1272000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	2814000	USD
	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	6905000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	4647000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-9435000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	57522000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-27738000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	56257000	USD
CY2018Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	39901000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	210656000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	104541000	USD
CY2018Q2	us-gaap	Stockholders Equity StockholdersEquity	1473992000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	49336000	USD
CY2018Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-9435000	USD
CY2018Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	22020000	USD
CY2018Q3	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
CY2018Q3	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	739000	USD
CY2018Q3	us-gaap	Stockholders Equity StockholdersEquity	1492612000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	1687376000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	51610000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	4647000	USD
CY2019Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	26784000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	229385000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
CY2019Q3	us-gaap	Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition	7167000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	1953401000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	1199057000	USD
	us-gaap	Net Income Loss NetIncomeLoss	132279000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-27738000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	63517000	USD
	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	250807000	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	1724000	USD
CY2018Q3	us-gaap	Stockholders Equity StockholdersEquity	1492612000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	1515854000	USD
	us-gaap	Net Income Loss NetIncomeLoss	153134000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	57522000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	72260000	USD
	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	316538000	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	8071000	USD
CY2019Q3	us-gaap	Cumulative Effect Of New Accounting Principle In Period Of Adoption CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	-25458000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	1953401000	USD
	us-gaap	Net Income Loss NetIncomeLoss	153134000	USD
	us-gaap	Net Income Loss NetIncomeLoss	132279000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	57000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	8707000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-11687000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-10088000	USD
	gbci	Accretion Amortizationof Discountsand Premiums Business Combinations AccretionAmortizationofDiscountsandPremiumsBusinessCombinations	2680000	USD
	gbci	Accretion Amortizationof Discountsand Premiums Business Combinations AccretionAmortizationofDiscountsandPremiumsBusinessCombinations	2962000	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	4630000	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	1237000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	671038000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	647932000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	633085000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	669344000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	23929000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	21495000	USD
	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	14158000	USD
	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	-756000	USD
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	1629000	USD
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	1782000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	6554000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	2523000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	13713000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	11543000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	288000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-2347000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5919000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4539000	USD
	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	6767000	USD
	gbci	Variable Interest Entities Investment Amortization VariableInterestEntitiesInvestmentAmortization	5070000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	5348000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	10581000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	367000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	6820000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	61000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	170000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-1730000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	10481000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	114440000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	167512000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	711268000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	224612000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	457299000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	259102000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	839835000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	550096000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	48940000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	55202000	USD
	us-gaap	Proceeds From Loan And Lease Originations And Principal Collections1 ProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections1	2497073000	USD
	us-gaap	Proceeds From Loan And Lease Originations And Principal Collections1 ProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections1	1908670000	USD
	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	2900692000	USD
	gbci	Payments For Loans Originated Or Acquired PaymentsForLoansOriginatedOrAcquired	2500098000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	14230000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	13984000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	2960000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	3370000	USD
	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	115436000	USD
	us-gaap	Proceeds From Sale Of Federal Home Loan Bank Stock ProceedsFromSaleOfFederalHomeLoanBankStock	73199000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	93397000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	62585000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1331000	USD
	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	7956000	USD
	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	30685000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-79334000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	-101268000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	56200000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-530694000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	377986000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	706469000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	161191000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	17001000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	-285000000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt Maturing In Three Months Or Less ProceedsFromRepaymentsOfShortTermDebtMaturingInThreeMonthsOrLess	-200000000	USD
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	151073000	USD
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	641000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	97000	USD
	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	-9823000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	70970000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	41542000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	277000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	1182000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	31954000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	470282000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	202594000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	107100000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	203790000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	200004000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	406384000	USD
CY2018Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	307104000	USD
	us-gaap	Interest Paid Net InterestPaidNet	33878000	USD
	us-gaap	Interest Paid Net InterestPaidNet	25925000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	33032000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	18440000	USD
	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	7000	USD
	us-gaap	Transfer Of Other Real Estate TransferOfOtherRealEstate	406000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	2347000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	4066000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3910000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	0	USD
	gbci	Dividends Declared But Not Paid Duringthe Period DividendsDeclaredButNotPaidDuringthePeriod	26874000	USD
	gbci	Dividends Declared But Not Paid Duringthe Period DividendsDeclaredButNotPaidDuringthePeriod	22240000	USD
	us-gaap	Stock Issued1 StockIssued1	316538000	USD
	us-gaap	Stock Issued1 StockIssued1	250807000	USD
	gbci	Cash Considerationfor Outstanding Shares CashConsiderationforOutstandingShares	16424000	USD
	gbci	Cash Considerationfor Outstanding Shares CashConsiderationforOutstandingShares	16265000	USD
	gbci	Business Combination Effective Settlementofa Pre Existing Relationship BusinessCombinationEffectiveSettlementofaPreExistingRelationship	0	USD
	gbci	Business Combination Effective Settlementofa Pre Existing Relationship BusinessCombinationEffectiveSettlementofaPreExistingRelationship	10054000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	1190267000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	1549158000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	1024141000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	1383756000	USD
CY2019Q3	gbci	Number Of Bank Divisions NumberOfBankDivisions	16	division
	gbci	Minimum Period Past Dueto Consider Loansas Delinquent MinimumPeriodPastDuetoConsiderLoansasDelinquent	P30D
	gbci	Minimum Period Past Dueto Consider Loansas Non Accrual MinimumPeriodPastDuetoConsiderLoansasNonAccrual	P90D
	gbci	Minimum Period Past Dueto Consider Loansas Non Accrual MinimumPeriodPastDuetoConsiderLoansasNonAccrual	P90D
	gbci	Minimum Period Past Dueto Consider Loansas Non Accrual MinimumPeriodPastDuetoConsiderLoansasNonAccrual	P90D
	gbci	Financing Receivable Allowancefor Credit Losses Numberof Quarters Usedto Evaluate Historical Loss Experience FinancingReceivableAllowanceforCreditLossesNumberofQuartersUsedtoEvaluateHistoricalLossExperience	12	quarter
	gbci	Maximum Term Leases Will Be Considered Shortterm MaximumTermLeasesWillBeConsideredShortterm	P12M
	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	54608000	USD
	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	56519000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2394617000	USD
CY2019Q3	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	65598000	USD
CY2019Q3	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	1179000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2459036000	USD
CY2019Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	234992000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	10567000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2019Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	245559000	USD
CY2019Q3	gbci	Debt Securities Amortized Cost Basis DebtSecuritiesAmortizedCostBasis	2629609000	USD
CY2019Q3	gbci	Securities Gross Unrealized Gain Accumulatedin Investments SecuritiesGrossUnrealizedGainAccumulatedinInvestments	76165000	USD
CY2019Q3	gbci	Securities Gross Unrealized Loss Accumulatedin Investments1 SecuritiesGrossUnrealizedLossAccumulatedinInvestments1	1179000	USD
CY2019Q3	gbci	Debt Securities Fair Value DebtSecuritiesFairValue	2704595000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2580520000	USD
CY2018Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	23360000	USD
CY2018Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	32217000	USD
CY2018Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2571663000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	297915000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	1380000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	11039000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	288256000	USD
CY2018Q4	gbci	Debt Securities Amortized Cost Basis DebtSecuritiesAmortizedCostBasis	2878435000	USD
CY2018Q4	gbci	Securities Gross Unrealized Gain Accumulatedin Investments SecuritiesGrossUnrealizedGainAccumulatedinInvestments	24740000	USD
CY2018Q4	gbci	Securities Gross Unrealized Loss Accumulatedin Investments1 SecuritiesGrossUnrealizedLossAccumulatedinInvestments1	43256000	USD
CY2018Q4	gbci	Debt Securities Fair Value DebtSecuritiesFairValue	2859919000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	160855000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	160980000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	0	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	0	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	209725000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	213094000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	10204000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	10580000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	215297000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	224814000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	75545000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	79647000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	361605000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	376983000	USD
CY2019Q3	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	149243000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	155332000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	947482000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	975871000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	234992000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	245559000	USD
CY2019Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2394617000	USD
CY2019Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	2459036000	USD
CY2019Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	234992000	USD
CY2019Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	245559000	USD
CY2019Q3	gbci	Proceedsfrom Salesand Callsof Debt Securities Availableforsale ProceedsfromSalesandCallsofDebtSecuritiesAvailableforsale	401701000	USD
CY2018Q3	gbci	Proceedsfrom Salesand Callsof Debt Securities Availableforsale ProceedsfromSalesandCallsofDebtSecuritiesAvailableforsale	12135000	USD
	gbci	Proceedsfrom Salesand Callsof Debt Securities Availableforsale ProceedsfromSalesandCallsofDebtSecuritiesAvailableforsale	878072000	USD
	gbci	Proceedsfrom Salesand Callsof Debt Securities Availableforsale ProceedsfromSalesandCallsofDebtSecuritiesAvailableforsale	245581000	USD
CY2019Q3	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	14329000	USD
CY2018Q3	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	188000	USD
	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	18613000	USD
	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	203000	USD
CY2019Q3	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	518000	USD
CY2018Q3	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	37000	USD
	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	4447000	USD
	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	398000	USD
CY2019Q3	gbci	Heldto Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldtoMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	16365000	USD
CY2018Q3	gbci	Heldto Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldtoMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	28435000	USD
	gbci	Heldto Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldtoMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	48940000	USD
	gbci	Heldto Maturity Securities Gross Realized Gains Losses Sale Proceeds HeldtoMaturitySecuritiesGrossRealizedGainsLossesSaleProceeds	57370000	USD
CY2019Q3	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	0	USD
CY2018Q3	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	12000	USD
	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	2000	USD
	gbci	Heldto Maturity Securities Sold Security Realized Gain HeldtoMaturitySecuritiesSoldSecurityRealizedGain	76000	USD
CY2019Q3	gbci	Heldto Maturity Securities Sold Security Realized Loss HeldtoMaturitySecuritiesSoldSecurityRealizedLoss	0	USD
CY2018Q3	gbci	Heldto Maturity Securities Sold Security Realized Loss HeldtoMaturitySecuritiesSoldSecurityRealizedLoss	530000	USD
	gbci	Heldto Maturity Securities Sold Security Realized Loss HeldtoMaturitySecuritiesSoldSecurityRealizedLoss	10000	USD
	gbci	Heldto Maturity Securities Sold Security Realized Loss HeldtoMaturitySecuritiesSoldSecurityRealizedLoss	637000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	290675000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	589000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	53518000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	590000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	344193000	USD
CY2019Q3	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	1179000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	444401000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	3224000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	1016813000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	28993000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	1461214000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	32217000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	87392000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	2778000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	126226000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	8261000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	213618000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	11039000	USD
	gbci	Financing Receivable Numberof Portfolio Segments FinancingReceivableNumberofPortfolioSegments	3	portfolio_segment
CY2019Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	9541088000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	8287549000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	125535000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	131239000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	9415553000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	8156310000	USD
CY2019Q3	gbci	Unamortized Loan Origination Feesand Costs UnamortizedLoanOriginationFeesandCosts	-6617000	USD
CY2018Q4	gbci	Unamortized Loan Origination Feesand Costs UnamortizedLoanOriginationFeesandCosts	-5685000	USD
CY2019Q3	gbci	Unamortized Discountsand Premiumson Loans UnamortizedDiscountsandPremiumsonLoans	-23620000	USD
CY2018Q4	gbci	Unamortized Discountsand Premiumson Loans UnamortizedDiscountsandPremiumsonLoans	-25172000	USD
	gbci	Weighted Average Interest Rate On Loans WeightedAverageInterestRateOnLoans	0.0521
CY2018	gbci	Weighted Average Interest Rate On Loans WeightedAverageInterestRateOnLoans	0.0497
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	129054000	USD
CY2019Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	0	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	5890000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	2371000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	125535000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	131564000	USD
CY2018Q3	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	3194000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	4294000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	2071000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	132535000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	131239000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	57000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	12090000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	6329000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	125535000	USD
CY2017Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	129568000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	8707000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	11905000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	6165000	USD
CY2018Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	132535000	USD
CY2019Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	108893000	USD
CY2019Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	9432195000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	9541088000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	107000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	125428000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	125535000	USD
CY2018Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	108788000	USD
CY2018Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	8178761000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	8287549000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	3223000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	128016000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	131239000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	40017000	USD
CY2019Q3	gbci	Financing Receivable Recorded Investment Past Due And Non Accrual Loans FinancingReceivableRecordedInvestmentPastDueAndNonAccrualLoans	77883000	USD
CY2019Q3	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	9463205000	USD
CY2019Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	9541088000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	47252000	USD
CY2018Q4	gbci	Financing Receivable Recorded Investment Past Due And Non Accrual Loans FinancingReceivableRecordedInvestmentPastDueAndNonAccrualLoans	82837000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	8204712000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	8287549000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	5610000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	5612000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	107000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	5624000	USD
	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	11626000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	103283000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	119582000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	99813000	USD
	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	94391000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	108893000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	125194000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	107000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	105437000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	106017000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	19197000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	19491000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	3223000	USD
CY2018	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	19519000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	89591000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	107486000	USD
CY2018	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	106747000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	108788000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	126977000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	3223000	USD
CY2018	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	126266000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	6	Loan
CY2019Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	3168000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	3168000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	Loan
CY2019Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
CY2018Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	2	Loan
CY2018Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	312000	USD
CY2018Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	312000	USD
CY2018Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	Loan
CY2018Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	47000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	14	Loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	5261000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	5247000	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
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	22	Loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	21582000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	21468000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	Loan
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	47000	USD
CY2019Q3	gbci	Tdr With Pre Modification Loan Balance For Which Oreo Was Received TdrWithPreModificationLoanBalanceForWhichOreoWasReceived	2982000	USD
CY2018Q3	gbci	Tdr With Pre Modification Loan Balance For Which Oreo Was Received TdrWithPreModificationLoanBalanceForWhichOreoWasReceived	5782000	USD
CY2019Q3	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	2233000	USD
CY2018Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	350000	USD
CY2019Q3	gbci	Real Estate Acquired Through Foreclosure Securedby Residential Real Estate RealEstateAcquiredThroughForeclosureSecuredbyResidentialRealEstate	2292000	USD
CY2018Q4	gbci	Real Estate Acquired Through Foreclosure Securedby Residential Real Estate RealEstateAcquiredThroughForeclosureSecuredbyResidentialRealEstate	698000	USD
CY2019Q3	gbci	Finance Lease Right Of Use Asset Gross FinanceLeaseRightOfUseAssetGross	951000	USD
CY2019Q3	gbci	Finance Lease Rightof Use Asset Accumulated Amortization FinanceLeaseRightofUseAssetAccumulatedAmortization	864000	USD
CY2019Q3	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	87000	USD
CY2019Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	41698000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Four LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFour	3142000	USD
CY2019Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	121000	USD
CY2019Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	44047000	USD
CY2019Q3	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P2Y
CY2019Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P18Y
CY2019Q3	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.053
CY2019Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.037
CY2019Q3	us-gaap	Finance Lease Liability Payments Due In Next Rolling Twelve Months FinanceLeaseLiabilityPaymentsDueInNextRollingTwelveMonths	23000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due Next Rolling Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextRollingTwelveMonths	3852000	USD
CY2019Q3	us-gaap	Finance Lease Liability Payments Due In Rolling Year Two FinanceLeaseLiabilityPaymentsDueInRollingYearTwo	92000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Two LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearTwo	3666000	USD
CY2019Q3	us-gaap	Finance Lease Liability Payments Due In Rolling Year Three FinanceLeaseLiabilityPaymentsDueInRollingYearThree	9000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Three LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearThree	3438000	USD
CY2019Q3	us-gaap	Finance Lease Liability Payments Due In Rolling Year Four FinanceLeaseLiabilityPaymentsDueInRollingYearFour	1000	USD
CY2019Q3	us-gaap	Finance Lease Liability Payments Due In Rolling Year Five FinanceLeaseLiabilityPaymentsDueInRollingYearFive	0	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due In Rolling Year Five LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFive	3128000	USD
CY2019Q3	us-gaap	Finance Lease Liability Payments Due In Rolling After Year Five FinanceLeaseLiabilityPaymentsDueInRollingAfterYearFive	0	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due After Rolling Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterRollingYearFive	46088000	USD
CY2019Q3	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	125000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	63314000	USD
CY2019Q3	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	22000	USD
CY2019Q3	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	2296000	USD
CY2019Q3	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	99000	USD
CY2019Q3	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	41751000	USD
CY2019Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	121000	USD
CY2019Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	44047000	USD
CY2019Q3	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	4000	USD
CY2019Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	19267000	USD
CY2019Q3	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	16000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	48000	USD
CY2019Q3	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	2000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	6000	USD
CY2019Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	1057000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	2967000	USD
CY2019Q3	us-gaap	Short Term Lease Cost ShortTermLeaseCost	102000	USD
	us-gaap	Short Term Lease Cost ShortTermLeaseCost	330000	USD
CY2019Q3	us-gaap	Variable Lease Cost VariableLeaseCost	236000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	657000	USD
CY2019Q3	us-gaap	Sublease Income SubleaseIncome	2000	USD
	us-gaap	Sublease Income SubleaseIncome	5000	USD
CY2019Q3	us-gaap	Lease Cost LeaseCost	1411000	USD
	us-gaap	Lease Cost LeaseCost	4003000	USD
CY2019Q3	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	2000	USD
CY2019Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	565000	USD
	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	6000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	1541000	USD
CY2019Q3	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	21000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	63000	USD
CY2019Q2	us-gaap	Goodwill Goodwill	330887000	USD
CY2018Q2	us-gaap	Goodwill Goodwill	289535000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	289586000	USD
CY2017Q4	us-gaap	Goodwill Goodwill	177811000	USD
CY2019Q3	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	125535000	USD
CY2018Q3	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	166836000	USD
	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	111724000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	456422000	USD
CY2018Q3	us-gaap	Goodwill Goodwill	289535000	USD
CY2019Q3	us-gaap	Goodwill Goodwill	456422000	USD
CY2018Q3	us-gaap	Goodwill Goodwill	289535000	USD
CY2019Q3	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	1609000	USD
CY2018Q3	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	1177000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	4504000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	3098000	USD
CY2019Q3	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	2202000	USD
CY2018Q3	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	1651000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	6169000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	4314000	USD
CY2019Q3	us-gaap	Securities Sold Under Agreements To Repurchase Gross Including Not Subject To Master Netting Arrangement SecuritiesSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	558752000	USD
CY2018Q4	us-gaap	Securities Sold Under Agreements To Repurchase Gross Including Not Subject To Master Netting Arrangement SecuritiesSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	396151000	USD
CY2019Q3	us-gaap	Pledged Financial Instruments Not Separately Reported Securities For Repurchase Agreements PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements	702809000	USD
CY2018Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Securities For Repurchase Agreements PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements	511294000	USD
CY2019Q3	us-gaap	Securities Sold Under Agreements To Repurchase Gross Including Not Subject To Master Netting Arrangement SecuritiesSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	558752000	USD
CY2018Q4	us-gaap	Securities Sold Under Agreements To Repurchase Gross Including Not Subject To Master Netting Arrangement SecuritiesSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement	396151000	USD
CY2019Q3	gbci	Consulting Fees ConsultingFees	1938000	USD
CY2018Q3	gbci	Consulting Fees ConsultingFees	1986000	USD
	gbci	Consulting Fees ConsultingFees	5715000	USD
	gbci	Consulting Fees ConsultingFees	5160000	USD
CY2019Q3	gbci	Debit Card Expense DebitCardExpense	1699000	USD
CY2018Q3	gbci	Debit Card Expense DebitCardExpense	533000	USD
	gbci	Debit Card Expense DebitCardExpense	5003000	USD
	gbci	Debit Card Expense DebitCardExpense	3321000	USD
CY2018Q3	gbci	Vie Writedowns Lossesand Other Expenses VIEWritedownsLossesandOtherExpenses	1118000	USD
	gbci	Vie Writedowns Lossesand Other Expenses VIEWritedownsLossesandOtherExpenses	2878000	USD
CY2019Q3	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	2058000	USD
CY2018Q3	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	1336000	USD
	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	4103000	USD
	us-gaap	Business Combination Integration Related Costs BusinessCombinationIntegrationRelatedCosts	6098000	USD
CY2019Q3	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	1245000	USD
CY2018Q3	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	1089000	USD
	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	3646000	USD
	gbci	Miscellaneous Employee Expenses MiscellaneousEmployeeExpenses	3022000	USD
CY2019Q3	gbci	Telephone Expenses TelephoneExpenses	1216000	USD
CY2018Q3	gbci	Telephone Expenses TelephoneExpenses	1187000	USD
	gbci	Telephone Expenses TelephoneExpenses	3601000	USD
	gbci	Telephone Expenses TelephoneExpenses	3350000	USD
CY2019Q3	us-gaap	Business Development BusinessDevelopment	1176000	USD
CY2018Q3	us-gaap	Business Development BusinessDevelopment	672000	USD
	us-gaap	Business Development BusinessDevelopment	3189000	USD
	us-gaap	Business Development BusinessDevelopment	1782000	USD
CY2019Q3	gbci	Vie Writedowns Lossesand Other Expenses VIEWritedownsLossesandOtherExpenses	1427000	USD
CY2019Q3	gbci	Atm Expenses ATMExpenses	299000	USD
	gbci	Vie Writedowns Lossesand Other Expenses VIEWritedownsLossesandOtherExpenses	2530000	USD
CY2019Q3	gbci	Loan Related Expenses LoanRelatedExpenses	924000	USD
CY2018Q3	gbci	Loan Related Expenses LoanRelatedExpenses	947000	USD
	gbci	Loan Related Expenses LoanRelatedExpenses	2726000	USD
	gbci	Loan Related Expenses LoanRelatedExpenses	2735000	USD
CY2019Q3	us-gaap	Postage Expense PostageExpense	831000	USD
CY2018Q3	us-gaap	Postage Expense PostageExpense	772000	USD
	us-gaap	Postage Expense PostageExpense	2487000	USD
	us-gaap	Postage Expense PostageExpense	2327000	USD
CY2019Q3	us-gaap	Supplies Expense SuppliesExpense	735000	USD
CY2018Q3	us-gaap	Supplies Expense SuppliesExpense	769000	USD
	us-gaap	Supplies Expense SuppliesExpense	2246000	USD
	us-gaap	Supplies Expense SuppliesExpense	2252000	USD
CY2019Q3	gbci	Deposit Related Expenses DepositRelatedExpenses	361000	USD
CY2018Q3	gbci	Deposit Related Expenses DepositRelatedExpenses	404000	USD
	gbci	Deposit Related Expenses DepositRelatedExpenses	1353000	USD
	gbci	Deposit Related Expenses DepositRelatedExpenses	871000	USD
CY2019Q3	us-gaap	Legal Fees LegalFees	338000	USD
CY2018Q3	gbci	Atm Expenses ATMExpenses	293000	USD
	gbci	Atm Expenses ATMExpenses	1312000	USD
	gbci	Atm Expenses ATMExpenses	927000	USD
CY2019Q3	gbci	Accounting Fees AccountingFees	365000	USD
CY2018Q3	gbci	Accounting Fees AccountingFees	383000	USD
	gbci	Accounting Fees AccountingFees	1290000	USD
	gbci	Accounting Fees AccountingFees	1194000	USD
CY2018Q3	us-gaap	Legal Fees LegalFees	464000	USD
	us-gaap	Legal Fees LegalFees	926000	USD
	us-gaap	Legal Fees LegalFees	1245000	USD
CY2019Q3	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	991000	USD
CY2018Q3	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	1165000	USD
	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	2679000	USD
	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	3516000	USD
CY2019Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15603000	USD
CY2018Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	13118000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	43154000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	40330000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-1979000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-29337000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-1599000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-27738000	USD
CY2018Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-29717000	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	60023000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	2501000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	57522000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	48095000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	51610000	USD
CY2019Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	154384	shares
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	49336000	USD
	us-gaap	Net Income Loss NetIncomeLoss	153134000	USD
	us-gaap	Net Income Loss NetIncomeLoss	132279000	USD
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	90294811	shares
CY2018Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	84518407	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	86911402	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	83294111	shares
CY2018Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	74715	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	170776	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	68212	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	90449195	shares
CY2018Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	84593122	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87082178	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	83362323	shares
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.57
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.58
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.76
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.59
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.57
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.58
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.76
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.59
CY2019Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	4037	shares
CY2018Q3	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	1360	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares

Files In Submission

Name	View Source	Status
0000868671-19-000055-index-headers.html	Edgar Link	pending
0000868671-19-000055-index.html	Edgar Link	pending
0000868671-19-000055.txt	Edgar Link	pending
0000868671-19-000055-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
gbci-09302019xex311.htm	Edgar Link	pending
gbci-09302019xex312.htm	Edgar Link	pending
gbci-09302019xex32.htm	Edgar Link	pending
gbci-20190930.htm	Edgar Link	pending
gbci-20190930.xsd	Edgar Link	pending
gbci-20190930_cal.xml	Edgar Link	unprocessable
gbci-20190930_def.xml	Edgar Link	unprocessable
gbci-20190930_htm.xml	Edgar Link	completed
gbci-20190930_lab.xml	Edgar Link	unprocessable
gbci-20190930_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
R12.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
R19.htm	Edgar Link	pending
R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
R32.htm	Edgar Link	pending
R33.htm	Edgar Link	pending
R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
R36.htm	Edgar Link	pending
R37.htm	Edgar Link	pending
R38.htm	Edgar Link	pending
R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R58.htm	Edgar Link	pending
R59.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R60.htm	Edgar Link	pending
R61.htm	Edgar Link	pending
R62.htm	Edgar Link	pending
R63.htm	Edgar Link	pending
R64.htm	Edgar Link	pending
R65.htm	Edgar Link	pending
R66.htm	Edgar Link	pending
R67.htm	Edgar Link	pending
R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R70.htm	Edgar Link	pending
R71.htm	Edgar Link	pending
R72.htm	Edgar Link	pending
R73.htm	Edgar Link	pending
R74.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending

Create your account

Find Stocks Worth Researching

Deeply Understand Businesses

Value Businesses Intelligently

$GBCI
GLACIER BANCORP, INC. Stock $gbci

2019 Q4 Form 10-Q Financial Statement

#000086867119000055 Filed on November 04, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$GBCI GLACIER BANCORP, INC. Stock $gbci

2019 Q4 Form 10-Q Financial Statement

#000086867119000055 Filed on November 04, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$GBCI
GLACIER BANCORP, INC. Stock $gbci