Investors Bancorp, Inc.

$ Overview Financials Valuation SEC Filings Company Website

2022 Q1 Form 10-K Financial Statement

#000159401222000022 Filed on March 01, 2022

Income Statement

Concept	2022 Q1	2021 Q4	2021

Balance Sheet

Concept	2022 Q1	2021 Q4	2021
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents		$288.0M
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		$129.3M
YoY Change		-7.43%
Goodwill		$116.2M
YoY Change		22.95%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets		$27.81B
YoY Change		6.85%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities
YoY Change
LONG-TERM LIABILITIES
Long-Term Debt
YoY Change
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities
YoY Change
TOTAL LIABILITIES
Total Short-Term Liabilities
Total Long-Term Liabilities
Total Liabilities		$24.87B
YoY Change		6.67%
SHAREHOLDERS EQUITY
Retained Earnings		$1.514B
YoY Change		13.07%
Common Stock		$3.619M
YoY Change		0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)		$1.375B
YoY Change		-0.06%
Treasury Stock Shares		113.9M shares
Shareholders Equity		$2.938B
YoY Change
Total Liabilities & Shareholders Equity		$27.81B
YoY Change		6.85%

Cashflow Statement

Concept	2022 Q1	2021 Q4	2021

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021	dei	Entity Central Index Key EntityCentralIndexKey	0001594012
CY2021	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
CY2021	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2021	dei	Amendment Flag AmendmentFlag	false
CY2019	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	http://fasb.org/us-gaap/2021-01-31#AccountingStandardsUpdate201613Member
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherAssets
CY2021Q4	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherAssets
CY2020Q4	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilities
CY2021Q4	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilities
CY2021	dei	Document Type DocumentType	10-K
CY2021	dei	Document Annual Report DocumentAnnualReport	true
CY2021	dei	Document Period End Date DocumentPeriodEndDate	2021-12-31
CY2021	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2021	dei	Document Transition Report DocumentTransitionReport	false
CY2021	dei	Entity File Number EntityFileNumber	001-36441
CY2021	dei	Entity Registrant Name EntityRegistrantName	Investors Bancorp, Inc.
CY2021	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2021	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	46-4702118
CY2021	dei	Entity Address Address Line1 EntityAddressAddressLine1	101 JFK Parkway,
CY2021	dei	Entity Address City Or Town EntityAddressCityOrTown	Short Hills,
CY2021	dei	Entity Address State Or Province EntityAddressStateOrProvince	NJ
CY2021	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	07078
CY2021	dei	City Area Code CityAreaCode	973
CY2021	dei	Local Phone Number LocalPhoneNumber	924-5100
CY2021	dei	Security12b Title Security12bTitle	Common
CY2021	dei	Trading Symbol TradingSymbol	ISBC
CY2021	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2021	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2021	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2021	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2021	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2021	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2021	dei	Entity Small Business EntitySmallBusiness	false
CY2021	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2021	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2021	dei	Entity Shell Company EntityShellCompany	false
CY2022Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	249038728	shares
CY2021Q2	dei	Entity Public Float EntityPublicFloat	3230000000	USD
CY2021	dei	Auditor Firm AuditorFirmId	185
CY2021	dei	Auditor Name AuditorName	KPMG LLP
CY2021	dei	Auditor Location AuditorLocation	Short Hills, New Jersey
CY2021Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	287990000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	170432000	USD
CY2021Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	8194000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	36000000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	2393540000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	2758437000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1651504000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1320872000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1593785000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1247853000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	22342612000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	20580451000	USD
CY2021Q4	isbc	Financing Receivable Loans Held For Sale Excluding Accrued Interest FinancingReceivableLoansHeldForSaleExcludingAccruedInterest	809000	USD
CY2020Q4	isbc	Financing Receivable Loans Held For Sale Excluding Accrued Interest FinancingReceivableLoansHeldForSaleExcludingAccruedInterest	30357000	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	176480000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Stock FederalHomeLoanBankStock	159829000	USD
CY2021Q4	us-gaap	Accrued Investment Income Receivable AccruedInvestmentIncomeReceivable	78636000	USD
CY2020Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2020Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	100000000	shares
CY2021Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	100000000	shares
CY2020Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2021Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2021Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2020Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2020Q4	us-gaap	Accrued Investment Income Receivable AccruedInvestmentIncomeReceivable	79705000	USD
CY2021Q4	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	2882000	USD
CY2020Q4	us-gaap	Real Estate Acquired Through Foreclosure RealEstateAcquiredThroughForeclosure	7115000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	129288000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	139663000	USD
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	199603000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	199981000	USD
CY2021Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	87251000	USD
CY2020Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	116805000	USD
CY2021Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	229358000	USD
CY2020Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	223714000	USD
CY2021Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	131993000	USD
CY2020Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	109633000	USD
CY2021Q4	us-gaap	Other Assets OtherAssets	144197000	USD
CY2020Q4	us-gaap	Other Assets OtherAssets	163184000	USD
CY2021Q4	us-gaap	Assets Assets	27806618000	USD
CY2020Q4	us-gaap	Assets Assets	26023159000	USD
CY2021Q4	us-gaap	Deposits Deposits	20824638000	USD
CY2020Q4	us-gaap	Deposits Deposits	19525419000	USD
CY2021Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	3535038000	USD
CY2020Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	3295790000	USD
CY2021Q4	us-gaap	Advance Payments By Borrowers For Taxes And Insurance AdvancePaymentsByBorrowersForTaxesAndInsurance	137438000	USD
CY2020Q4	us-gaap	Advance Payments By Borrowers For Taxes And Insurance AdvancePaymentsByBorrowersForTaxesAndInsurance	115729000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	212678000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	212559000	USD
CY2021Q4	us-gaap	Other Liabilities OtherLiabilities	158398000	USD
CY2020Q4	us-gaap	Other Liabilities OtherLiabilities	163659000	USD
CY2021Q4	us-gaap	Liabilities Liabilities	24868190000	USD
CY2020Q4	us-gaap	Liabilities Liabilities	23313156000	USD
CY2021Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2020Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2021Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2021Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2021Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	1000000000	shares
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	1000000000	shares
CY2020Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	361869872	shares
CY2021Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	361869872	shares
CY2021Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	247997266	shares
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	247929216	shares
CY2021Q4	us-gaap	Common Stock Value CommonStockValue	3619000	USD
CY2020Q4	us-gaap	Common Stock Value CommonStockValue	3619000	USD
CY2021Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	2872103000	USD
CY2020Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	2858663000	USD
CY2021Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1513970000	USD
CY2020Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1339003000	USD
CY2021Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	113872606	shares
CY2020Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	113940656	shares
CY2021Q4	us-gaap	Treasury Stock Value TreasuryStockValue	1375126000	USD
CY2020Q4	us-gaap	Treasury Stock Value TreasuryStockValue	1375996000	USD
CY2021Q4	us-gaap	Unearned Esop Shares UnearnedESOPShares	69845000	USD
CY2020Q4	us-gaap	Unearned Esop Shares UnearnedESOPShares	75270000	USD
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-6293000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-40016000	USD
CY2020	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	99619000	USD
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	2938428000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	2710003000	USD
CY2021Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	27806618000	USD
CY2020Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	26023159000	USD
CY2021	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	836171000	USD
CY2020	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	871411000	USD
CY2019	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	912091000	USD
CY2021	us-gaap	Dividend Income Equity Securities Operating DividendIncomeEquitySecuritiesOperating	458000	USD
CY2020	us-gaap	Dividend Income Equity Securities Operating DividendIncomeEquitySecuritiesOperating	362000	USD
CY2019	us-gaap	Dividend Income Equity Securities Operating DividendIncomeEquitySecuritiesOperating	143000	USD
CY2021	us-gaap	Interest Income Securities Other Us Government InterestIncomeSecuritiesOtherUSGovernment	2237000	USD
CY2020	us-gaap	Interest Income Securities Other Us Government InterestIncomeSecuritiesOtherUSGovernment	1517000	USD
CY2019	us-gaap	Interest Income Securities Other Us Government InterestIncomeSecuritiesOtherUSGovernment	1212000	USD
CY2021	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	56539000	USD
CY2020	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	77925000	USD
CY2019	us-gaap	Interest Income Securities Mortgage Backed InterestIncomeSecuritiesMortgageBacked	95133000	USD
CY2021	us-gaap	Interest Income Securities State And Municipal InterestIncomeSecuritiesStateAndMunicipal	14039000	USD
CY2020	us-gaap	Interest Income Securities State And Municipal InterestIncomeSecuritiesStateAndMunicipal	13480000	USD
CY2019	us-gaap	Interest Income Securities State And Municipal InterestIncomeSecuritiesStateAndMunicipal	11494000	USD
CY2021	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	648000	USD
CY2020	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	1460000	USD
CY2019	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	2805000	USD
CY2021	us-gaap	Interest Income Federal Home Loan Bank Advances InterestIncomeFederalHomeLoanBankAdvances	8546000	USD
CY2020	us-gaap	Interest Income Federal Home Loan Bank Advances InterestIncomeFederalHomeLoanBankAdvances	14739000	USD
CY2019	us-gaap	Interest Income Federal Home Loan Bank Advances InterestIncomeFederalHomeLoanBankAdvances	17341000	USD
CY2021	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	918638000	USD
CY2020	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	980894000	USD
CY2019	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	1040219000	USD
CY2021	us-gaap	Interest Expense Deposits InterestExpenseDeposits	67905000	USD
CY2020	us-gaap	Interest Expense Deposits InterestExpenseDeposits	155589000	USD
CY2019	us-gaap	Interest Expense Deposits InterestExpenseDeposits	261857000	USD
CY2021	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	79718000	USD
CY2019	us-gaap	Interest Expense Borrowings InterestExpenseBorrowings	123289000	USD
CY2021	us-gaap	Interest Expense InterestExpense	147623000	USD
CY2020	us-gaap	Interest Expense InterestExpense	255208000	USD
CY2019	us-gaap	Interest Expense InterestExpense	385146000	USD
CY2021	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	771015000	USD
CY2020	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	725686000	USD
CY2019	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	655073000	USD
CY2021	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-48676000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	70158000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-1000000	USD
CY2021	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	819691000	USD
CY2020	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	655528000	USD
CY2019	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	656073000	USD
CY2021	us-gaap	Investment Banking Advisory Brokerage And Underwriting Fees And Commissions InvestmentBankingAdvisoryBrokerageAndUnderwritingFeesAndCommissions	22080000	USD
CY2020	us-gaap	Investment Banking Advisory Brokerage And Underwriting Fees And Commissions InvestmentBankingAdvisoryBrokerageAndUnderwritingFeesAndCommissions	17916000	USD
CY2019	us-gaap	Investment Banking Advisory Brokerage And Underwriting Fees And Commissions InvestmentBankingAdvisoryBrokerageAndUnderwritingFeesAndCommissions	23604000	USD
CY2021	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	6548000	USD
CY2020	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	6638000	USD
CY2019	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	6542000	USD
CY2021	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	6911000	USD
CY2020	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	16226000	USD
CY2019	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	5345000	USD
CY2021	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	506000	USD
CY2020	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	406000	USD
CY2019	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-5536000	USD
CY2021	isbc	Sale And Leaseback Transaction Gain Loss Gross SaleAndLeasebackTransactionGainLossGross	0	USD
CY2020	isbc	Sale And Leaseback Transaction Gain Loss Gross SaleAndLeasebackTransactionGainLossGross	23129000	USD
CY2019	isbc	Sale And Leaseback Transaction Gain Loss Gross SaleAndLeasebackTransactionGainLossGross	0	USD
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	86000	USD
CY2020	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	1054000	USD
CY2019	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	1145000	USD
CY2021	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	28332000	USD
CY2021	us-gaap	Noninterest Expense NoninterestExpense	455741000	USD
CY2020	us-gaap	Noninterest Expense NoninterestExpense	449505000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	422754000	USD
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	428413000	USD
CY2021	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	12083000	USD
CY2020	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	9551000	USD
CY2019	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	13893000	USD
CY2020	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	25149000	USD
CY2019	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	22313000	USD
CY2021	us-gaap	Noninterest Income NoninterestIncome	64463000	USD
CY2020	us-gaap	Noninterest Income NoninterestIncome	90518000	USD
CY2019	us-gaap	Noninterest Income NoninterestIncome	53413000	USD
CY2021	us-gaap	Labor And Related Expense LaborAndRelatedExpense	245065000	USD
CY2020	us-gaap	Labor And Related Expense LaborAndRelatedExpense	240970000	USD
CY2019	us-gaap	Labor And Related Expense LaborAndRelatedExpense	243782000	USD
CY2021	us-gaap	Occupancy Net OccupancyNet	76788000	USD
CY2020	us-gaap	Occupancy Net OccupancyNet	77754000	USD
CY2019	us-gaap	Occupancy Net OccupancyNet	63996000	USD
CY2021	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	12350000	USD
CY2020	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	14276000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	91248000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	313333000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	296541000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	286732000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	115080000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	74961000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	221580000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	195484000	USD
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.33
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.94
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.75
CY2019	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	13200000	USD
CY2021	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	2254000	USD
CY2020	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	2133000	USD
CY2019	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	2222000	USD
CY2021	us-gaap	Professional Fees ProfessionalFees	26483000	USD
CY2020	us-gaap	Professional Fees ProfessionalFees	16220000	USD
CY2019	us-gaap	Professional Fees ProfessionalFees	17308000	USD
CY2021	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	39042000	USD
CY2020	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	35702000	USD
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.74
CY2019	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	31987000	USD
CY2021	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-10159000	USD
CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-24098000	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2021	us-gaap	Other Noninterest Expense OtherNoninterestExpense	31517000	USD
CY2020	us-gaap	Other Noninterest Expense OtherNoninterestExpense	28801000	USD
CY2019	us-gaap	Other Noninterest Expense OtherNoninterestExpense	36366000	USD
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.33
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.94
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	235315487	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	235761457	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	262202598	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	236436081	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	235838808	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	262519788	shares
CY2021	us-gaap	Net Income Loss NetIncomeLoss	313333000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	221580000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	195484000	USD
CY2021	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent	-1666000	USD
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent	2795000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentNetOfTaxPortionAttributableToParent	3672000	USD
CY2021	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-41756000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	27748000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	34119000	USD
CY2021	isbc	Other Comprehensive Loss Held To Maturity Security Adjustment From Aoci For Accretion Of Transfers From Available For Sale To Held To Maturity After Tax OtherComprehensiveLossHeldToMaturitySecurityAdjustmentFromAOCIForAccretionOfTransfersFromAvailableForSaleToHeldToMaturityAfterTax	107000	USD
CY2020	isbc	Other Comprehensive Loss Held To Maturity Security Adjustment From Aoci For Accretion Of Transfers From Available For Sale To Held To Maturity After Tax OtherComprehensiveLossHeldToMaturitySecurityAdjustmentFromAOCIForAccretionOfTransfersFromAvailableForSaleToHeldToMaturityAfterTax	202000	USD
CY2019	isbc	Other Comprehensive Loss Held To Maturity Security Adjustment From Aoci For Accretion Of Transfers From Available For Sale To Held To Maturity After Tax OtherComprehensiveLossHeldToMaturitySecurityAdjustmentFromAOCIForAccretionOfTransfersFromAvailableForSaleToHeldToMaturityAfterTax	535000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	299000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	-4221000	USD
CY2021	us-gaap	Other Comprehensive Loss Held To Maturity Security Adjustment From Aoci For Accretion Of Noncredit Portion Of Otti After Tax OtherComprehensiveLossHeldToMaturitySecurityAdjustmentFromAociForAccretionOfNoncreditPortionOfOttiAfterTax	735000	USD
CY2020	us-gaap	Other Comprehensive Loss Held To Maturity Security Adjustment From Aoci For Accretion Of Noncredit Portion Of Otti After Tax OtherComprehensiveLossHeldToMaturitySecurityAdjustmentFromAociForAccretionOfNoncreditPortionOfOttiAfterTax	820000	USD
CY2019	us-gaap	Other Comprehensive Loss Held To Maturity Security Adjustment From Aoci For Accretion Of Noncredit Portion Of Otti After Tax OtherComprehensiveLossHeldToMaturitySecurityAdjustmentFromAociForAccretionOfNoncreditPortionOfOttiAfterTax	768000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	73270000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-47369000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-43024000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	33723000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-21394000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-7053000	USD
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	347056000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	200186000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	188431000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	3005330000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	195484000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-7053000	USD
CY2019	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	39365145	shares
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	475946000	USD
CY2019	us-gaap	Stock Issued During Period Shares Restricted Stock Award Gross StockIssuedDuringPeriodSharesRestrictedStockAwardGross	2360919	shares
CY2019	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	19968000	USD
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	814000	USD
CY2019	us-gaap	Stock Issued During Period Shares Share Based Compensation Forfeited StockIssuedDuringPeriodSharesShareBasedCompensationForfeited	1940788	shares
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation Forfeited StockIssuedDuringPeriodValueShareBasedCompensationForfeited	0	USD
CY2019	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.44
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	122163000	USD
CY2019	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	5516000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	2621950000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	221580000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-21394000	USD
CY2020	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	20881000	USD
CY2020	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2377814	shares
CY2020	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	23920000	USD
CY2020	us-gaap	Stock Issued During Period Shares Restricted Stock Award Gross StockIssuedDuringPeriodSharesRestrictedStockAwardGross	91249	shares
CY2020	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	14772000	USD
CY2020	us-gaap	Stock Issued During Period Shares Share Based Compensation Forfeited StockIssuedDuringPeriodSharesShareBasedCompensationForfeited	23141	shares
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation Forfeited StockIssuedDuringPeriodValueShareBasedCompensationForfeited	0	USD
CY2020	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.48
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	119675000	USD
CY2020	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	4300000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	2710003000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	313333000	USD
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	33723000	USD
CY2021	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	975469	shares
CY2021	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	12124000	USD
CY2021	us-gaap	Stock Issued During Period Shares Restricted Stock Award Gross StockIssuedDuringPeriodSharesRestrictedStockAwardGross	262281	shares
CY2021	us-gaap	Stock Issued During Period Value Restricted Stock Award Gross StockIssuedDuringPeriodValueRestrictedStockAwardGross	0	USD
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	14314000	USD
CY2021	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	9987000	USD
CY2021	us-gaap	Stock Issued During Period Shares Share Based Compensation Forfeited StockIssuedDuringPeriodSharesShareBasedCompensationForfeited	33351	shares
CY2021	us-gaap	Stock Issued During Period Value Share Based Compensation Forfeited StockIssuedDuringPeriodValueShareBasedCompensationForfeited	0	USD
CY2021	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.56
CY2021	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	138607000	USD
CY2021	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	7799000	USD
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	2938428000	USD
CY2021	us-gaap	Net Income Loss NetIncomeLoss	313333000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	221580000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	195484000	USD
CY2021	us-gaap	Employee Benefits And Share Based Compensation EmployeeBenefitsAndShareBasedCompensation	22113000	USD
CY2020	us-gaap	Employee Benefits And Share Based Compensation EmployeeBenefitsAndShareBasedCompensation	19072000	USD
CY2019	us-gaap	Employee Benefits And Share Based Compensation EmployeeBenefitsAndShareBasedCompensation	25484000	USD
CY2021	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-9418000	USD
CY2020	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-11468000	USD
CY2019	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-9251000	USD
CY2021	us-gaap	Amortization Of Debt Discount Premium AmortizationOfDebtDiscountPremium	-1076000	USD
CY2020	us-gaap	Amortization Of Debt Discount Premium AmortizationOfDebtDiscountPremium	1151000	USD
CY2019	us-gaap	Amortization Of Debt Discount Premium AmortizationOfDebtDiscountPremium	-3730000	USD
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1311000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1471000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1520000	USD
CY2021	isbc	Amortization Of Debt Modification Costs And Premium On Borrowings AmortizationOfDebtModificationCostsAndPremiumOnBorrowings	2248000	USD
CY2020	isbc	Amortization Of Debt Modification Costs And Premium On Borrowings AmortizationOfDebtModificationCostsAndPremiumOnBorrowings	2225000	USD
CY2019	isbc	Amortization Of Debt Modification Costs And Premium On Borrowings AmortizationOfDebtModificationCostsAndPremiumOnBorrowings	1186000	USD
CY2021	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-48676000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	70158000	USD
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-1000000	USD
CY2021	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-10159000	USD
CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-24098000	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2021	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	21614000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	21350000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	19579000	USD
CY2021	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	506000	USD
CY2020	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	406000	USD
CY2019	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-5536000	USD
CY2021	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	144989000	USD
CY2020	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	564527000	USD
CY2019	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	269773000	USD
CY2021	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	179427000	USD
CY2020	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	579788000	USD
CY2019	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	247640000	USD
CY2021	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	4891000	USD
CY2020	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	15822000	USD
CY2019	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	3590000	USD
CY2021	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	86000	USD
CY2020	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	1054000	USD
CY2019	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	1145000	USD
CY2021	isbc	Sale And Leaseback Transaction Gain Loss Gross SaleAndLeasebackTransactionGainLossGross	0	USD
CY2020	isbc	Sale And Leaseback Transaction Gain Loss Gross SaleAndLeasebackTransactionGainLossGross	23129000	USD
CY2019	isbc	Sale And Leaseback Transaction Gain Loss Gross SaleAndLeasebackTransactionGainLossGross	0	USD
CY2021	isbc	Income On Bank Owned Life Insurance IncomeOnBankOwnedLifeInsurance	6548000	USD
CY2020	isbc	Income On Bank Owned Life Insurance IncomeOnBankOwnedLifeInsurance	6638000	USD
CY2019	isbc	Income On Bank Owned Life Insurance IncomeOnBankOwnedLifeInsurance	6542000	USD
CY2021	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	25893000	USD
CY2020	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	21551000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	17608000	USD
CY2021	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-2077000	USD
CY2020	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-891000	USD
CY2019	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	1812000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	14379000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-34190000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	45624000	USD
CY2021	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-116830000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	121081000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	42170000	USD
CY2021	us-gaap	Increase Decrease In Operating Liabilities IncreaseDecreaseInOperatingLiabilities	-17250000	USD
CY2020	us-gaap	Increase Decrease In Operating Liabilities IncreaseDecreaseInOperatingLiabilities	16341000	USD
CY2019	us-gaap	Increase Decrease In Operating Liabilities IncreaseDecreaseInOperatingLiabilities	-78496000	USD
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	494780000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	224297000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	160654000	USD
CY2021	us-gaap	Payments To Acquire Loans Held For Investment PaymentsToAcquireLoansHeldForInvestment	103686000	USD
CY2020	us-gaap	Payments To Acquire Loans Held For Investment PaymentsToAcquireLoansHeldForInvestment	158420000	USD
CY2019	us-gaap	Payments To Acquire Loans Held For Investment PaymentsToAcquireLoansHeldForInvestment	427053000	USD
CY2021	isbc	Payments For Proceeds From Loan Originations PaymentsForProceedsFromLoanOriginations	1481130000	USD
CY2020	isbc	Payments For Proceeds From Loan Originations PaymentsForProceedsFromLoanOriginations	-1055802000	USD
CY2019	isbc	Payments For Proceeds From Loan Originations PaymentsForProceedsFromLoanOriginations	-101227000	USD
CY2021	isbc	Proceeds From Sale Of Loans And Leases Receivable ProceedsFromSaleOfLoansAndLeasesReceivable	88412000	USD
CY2020	isbc	Proceeds From Sale Of Loans And Leases Receivable ProceedsFromSaleOfLoansAndLeasesReceivable	380671000	USD
CY2019	isbc	Proceeds From Sale Of Loans And Leases Receivable ProceedsFromSaleOfLoansAndLeasesReceivable	227522000	USD
CY2021	isbc	Gain On Disposition Of Loans Receivable GainOnDispositionOfLoansReceivable	2020000	USD
CY2020	isbc	Gain On Disposition Of Loans Receivable GainOnDispositionOfLoansReceivable	404000	USD
CY2019	isbc	Gain On Disposition Of Loans Receivable GainOnDispositionOfLoansReceivable	1755000	USD
CY2021	isbc	Gain On Disposition Of Leased Equipment GainOnDispositionOfLeasedEquipment	3380000	USD
CY2020	isbc	Gain On Disposition Of Leased Equipment GainOnDispositionOfLeasedEquipment	2086000	USD
CY2019	isbc	Gain On Disposition Of Leased Equipment GainOnDispositionOfLeasedEquipment	5698000	USD
CY2021	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	1421000	USD
CY2020	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	7393000	USD
CY2019	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	6498000	USD
CY2021	isbc	Proceeds From Sale Of Equity Securities ProceedsFromSaleOfEquitySecurities	33983000	USD
CY2020	isbc	Proceeds From Sale Of Equity Securities ProceedsFromSaleOfEquitySecurities	0	USD
CY2019	isbc	Proceeds From Sale Of Equity Securities ProceedsFromSaleOfEquitySecurities	0	USD
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	960934000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	1020929000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	492419000	USD
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	8171000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	399435000	USD
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	302881000	USD
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	278532000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	251574000	USD
CY2021	isbc	Payment To Acquire Equity Securities PaymentToAcquireEquitySecurities	6068000	USD
CY2020	isbc	Payment To Acquire Equity Securities PaymentToAcquireEquitySecurities	29705000	USD
CY2019	isbc	Payment To Acquire Equity Securities PaymentToAcquireEquitySecurities	96000	USD
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	666822000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1005649000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	1034131000	USD
CY2021	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	647881000	USD
CY2020	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	372712000	USD
CY2019	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	238670000	USD
CY2021	us-gaap	Proceeds From Sale Of Federal Reserve Stock ProceedsFromSaleOfFederalReserveStock	89575000	USD
CY2020	us-gaap	Proceeds From Sale Of Federal Reserve Stock ProceedsFromSaleOfFederalReserveStock	182182000	USD
CY2019	us-gaap	Proceeds From Sale Of Federal Reserve Stock ProceedsFromSaleOfFederalReserveStock	303245000	USD
CY2021	us-gaap	Payments To Acquire Federal Reserve Stock PaymentsToAcquireFederalReserveStock	106226000	USD
CY2020	us-gaap	Payments To Acquire Federal Reserve Stock PaymentsToAcquireFederalReserveStock	74171000	USD
CY2019	us-gaap	Payments To Acquire Federal Reserve Stock PaymentsToAcquireFederalReserveStock	310230000	USD
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	10875000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	17755000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	11761000	USD
CY2021	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	0	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	49970000	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	0	USD
CY2021	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	904000	USD
CY2020	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1439000	USD
CY2019	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
CY2021	isbc	Cash Received Net Of Cash Consideration Paid For Acquisitions CashReceivedNetOfCashConsiderationPaidForAcquisitions	391640000	USD
CY2020	isbc	Cash Received Net Of Cash Consideration Paid For Acquisitions CashReceivedNetOfCashConsiderationPaidForAcquisitions	7274000	USD
CY2019	isbc	Cash Received Net Of Cash Consideration Paid For Acquisitions CashReceivedNetOfCashConsiderationPaidForAcquisitions	0	USD
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1150167000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	1323290000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-247474000	USD
CY2021	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	666830000	USD
CY2020	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	1175200000	USD
CY2019	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	280069000	USD
CY2021	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	1588000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	1579000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	2000	USD
CY2021	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	0	USD
CY2020	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	0	USD
CY2019	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	197584000	USD
CY2021	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	837000000	USD
CY2020	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	-1548397000	USD
CY2019	us-gaap	Proceeds From Repayments Of Other Debt ProceedsFromRepaymentsOfOtherDebt	192660000	USD
CY2021	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	610159000	USD
CY2020	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	1024098000	USD
CY2019	us-gaap	Payments Of Debt Extinguishment Costs PaymentsOfDebtExtinguishmentCosts	0	USD
CY2021	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	21606000	USD
CY2020	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	-9601000	USD
CY2019	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	-8172000	USD
CY2021	us-gaap	Payments Of Dividends PaymentsOfDividends	138607000	USD
CY2020	us-gaap	Payments Of Dividends PaymentsOfDividends	119675000	USD
CY2019	us-gaap	Payments Of Dividends PaymentsOfDividends	122163000	USD
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	9987000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	0	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	814000	USD
CY2021	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	12124000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	23920000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	475946000	USD
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	772945000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-1552070000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	64844000	USD
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	117558000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-4483000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-21976000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	170432000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	174915000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	196891000	USD
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	287990000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	170432000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	174915000	USD
CY2021	isbc	Real Estate Acquired Foreclosure RealEstateAcquiredForeclosure	344000	USD
CY2020	isbc	Real Estate Acquired Foreclosure RealEstateAcquiredForeclosure	1050000	USD
CY2019	isbc	Real Estate Acquired Foreclosure RealEstateAcquiredForeclosure	12567000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	268284000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	390359000	USD
CY2021	isbc	Other Repossessed Assets Transferred To Active Leases OtherRepossessedAssetsTransferredToActiveLeases	3242000	USD
CY2020	isbc	Other Repossessed Assets Transferred To Active Leases OtherRepossessedAssetsTransferredToActiveLeases	0	USD
CY2019	isbc	Other Repossessed Assets Transferred To Active Leases OtherRepossessedAssetsTransferredToActiveLeases	0	USD
CY2021	us-gaap	Interest Paid Net InterestPaidNet	150612000	USD
CY2021	us-gaap	Income Taxes Paid IncomeTaxesPaid	110025000	USD
CY2020	us-gaap	Income Taxes Paid IncomeTaxesPaid	88450000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	36146000	USD
CY2021	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	0	USD
CY2020	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	0	USD
CY2019	us-gaap	Debt Securities Held To Maturity Transfer Amount DebtSecuritiesHeldToMaturityTransferAmount	393359000	USD
CY2021	us-gaap	Transfer Of Portfolio Loans And Leases To Held For Sale1 TransferOfPortfolioLoansAndLeasesToHeldForSale1	0	USD
CY2020	us-gaap	Transfer Of Portfolio Loans And Leases To Held For Sale1 TransferOfPortfolioLoansAndLeasesToHeldForSale1	0	USD
CY2019	us-gaap	Transfer Of Portfolio Loans And Leases To Held For Sale1 TransferOfPortfolioLoansAndLeasesToHeldForSale1	28373000	USD
CY2021	isbc	Investment In Low Income Housing Tax Credit InvestmentInLowIncomeHousingTaxCredit	10000000	USD
CY2020	isbc	Investment In Low Income Housing Tax Credit InvestmentInLowIncomeHousingTaxCredit	0	USD
CY2019	isbc	Investment In Low Income Housing Tax Credit InvestmentInLowIncomeHousingTaxCredit	10000000	USD
CY2021	isbc	Right Of Use Asset Obtained In Exchange For Operating Lease Liability Excluding Acquisitions RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilityExcludingAcquisitions	16372000	USD
CY2020	isbc	Right Of Use Asset Obtained In Exchange For Operating Lease Liability Excluding Acquisitions RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilityExcludingAcquisitions	43062000	USD
CY2019	isbc	Right Of Use Asset Obtained In Exchange For Operating Lease Liability Excluding Acquisitions RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilityExcludingAcquisitions	2996000	USD
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Investments Acquired1 NoncashOrPartNoncashAcquisitionInvestmentsAcquired1	0	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Investments Acquired1 NoncashOrPartNoncashAcquisitionInvestmentsAcquired1	51524000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Investments Acquired1 NoncashOrPartNoncashAcquisitionInvestmentsAcquired1	0	USD
CY2021	isbc	Noncash Or Part Noncash Acquisition Investments Acquired Debt Securities Held To Maturity NoncashOrPartNoncashAcquisitionInvestmentsAcquiredDebtSecuritiesHeldToMaturity	0	USD
CY2020	isbc	Noncash Or Part Noncash Acquisition Investments Acquired Debt Securities Held To Maturity NoncashOrPartNoncashAcquisitionInvestmentsAcquiredDebtSecuritiesHeldToMaturity	8402000	USD
CY2019	isbc	Noncash Or Part Noncash Acquisition Investments Acquired Debt Securities Held To Maturity NoncashOrPartNoncashAcquisitionInvestmentsAcquiredDebtSecuritiesHeldToMaturity	0	USD
CY2021	isbc	Noncash Or Part Noncash Acquisition Loans Acquired NoncashOrPartNoncashAcquisitionLoansAcquired	212538000	USD
CY2020	isbc	Noncash Or Part Noncash Acquisition Loans Acquired NoncashOrPartNoncashAcquisitionLoansAcquired	443499000	USD
CY2019	isbc	Noncash Or Part Noncash Acquisition Loans Acquired NoncashOrPartNoncashAcquisitionLoansAcquired	0	USD
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	364000	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	485000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	0	USD
CY2021	isbc	Noncash Or Part Noncash Acquisition Accrued Interest Receivable NoncashOrPartNoncashAcquisitionAccruedInterestReceivable	1008000	USD
CY2020	isbc	Noncash Or Part Noncash Acquisition Accrued Interest Receivable NoncashOrPartNoncashAcquisitionAccruedInterestReceivable	1283000	USD
CY2019	isbc	Noncash Or Part Noncash Acquisition Accrued Interest Receivable NoncashOrPartNoncashAcquisitionAccruedInterestReceivable	0	USD
CY2021	isbc	Noncash Or Part Noncash Acquisition Right Of Use Assets Leases NoncashOrPartNoncashAcquisitionRightOfUseAssetsLeases	9310000	USD
CY2020	isbc	Noncash Or Part Noncash Acquisition Right Of Use Assets Leases NoncashOrPartNoncashAcquisitionRightOfUseAssetsLeases	3697000	USD
CY2019	isbc	Noncash Or Part Noncash Acquisition Right Of Use Assets Leases NoncashOrPartNoncashAcquisitionRightOfUseAssetsLeases	0	USD
CY2021	isbc	Noncash Or Part Noncash Acquisition Deferred Tax Asset NoncashOrPartNoncashAcquisitionDeferredTaxAsset	1212000	USD
CY2020	isbc	Noncash Or Part Noncash Acquisition Deferred Tax Asset NoncashOrPartNoncashAcquisitionDeferredTaxAsset	3915000	USD
CY2019	isbc	Noncash Or Part Noncash Acquisition Deferred Tax Asset NoncashOrPartNoncashAcquisitionDeferredTaxAsset	0	USD
CY2021	isbc	Noncash Or Part Noncash Acquisition Intangible Assets Net NoncashOrPartNoncashAcquisitionIntangibleAssetsNet	25291000	USD
CY2020	isbc	Noncash Or Part Noncash Acquisition Intangible Assets Net NoncashOrPartNoncashAcquisitionIntangibleAssetsNet	14491000	USD
CY2019	isbc	Noncash Or Part Noncash Acquisition Intangible Assets Net NoncashOrPartNoncashAcquisitionIntangibleAssetsNet	0	USD
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Other Assets Acquired1 NoncashOrPartNoncashAcquisitionOtherAssetsAcquired1	509000	USD
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Debt Assumed1 NoncashOrPartNoncashAcquisitionDebtAssumed1	0	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Other Assets Acquired1 NoncashOrPartNoncashAcquisitionOtherAssetsAcquired1	705000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Other Assets Acquired1 NoncashOrPartNoncashAcquisitionOtherAssetsAcquired1	0	USD
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	250232000	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	528001000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	0	USD
CY2021	isbc	Noncash Or Part Noncash Acquisition Deposits Assumed NoncashOrPartNoncashAcquisitionDepositsAssumed	632389000	USD
CY2020	isbc	Noncash Or Part Noncash Acquisition Deposits Assumed NoncashOrPartNoncashAcquisitionDepositsAssumed	489881000	USD
CY2019	isbc	Noncash Or Part Noncash Acquisition Deposits Assumed NoncashOrPartNoncashAcquisitionDepositsAssumed	0	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Debt Assumed1 NoncashOrPartNoncashAcquisitionDebtAssumed1	14851000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Debt Assumed1 NoncashOrPartNoncashAcquisitionDebtAssumed1	0	USD
CY2021	isbc	Noncash Or Part Noncash Acquisition Deposits Advance Payment By Borrowers Assumed NoncashOrPartNoncashAcquisitionDepositsAdvancePaymentByBorrowersAssumed	103000	USD
CY2020	isbc	Noncash Or Part Noncash Acquisition Deposits Advance Payment By Borrowers Assumed NoncashOrPartNoncashAcquisitionDepositsAdvancePaymentByBorrowersAssumed	3611000	USD
CY2019	isbc	Noncash Or Part Noncash Acquisition Deposits Advance Payment By Borrowers Assumed NoncashOrPartNoncashAcquisitionDepositsAdvancePaymentByBorrowersAssumed	0	USD
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Other Liabilities Assumed1 NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1	9380000	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Other Liabilities Assumed1 NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1	6051000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Other Liabilities Assumed1 NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1	0	USD
CY2021	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	641872000	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	514394000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	0	USD
CY2021	isbc	Net Non Cash Assets Acquired NetNonCashAssetsAcquired	-391640000	USD
CY2020	isbc	Net Non Cash Assets Acquired NetNonCashAssetsAcquired	13607000	USD
CY2019	isbc	Net Non Cash Assets Acquired NetNonCashAssetsAcquired	0	USD
CY2021	isbc	Loan Delinquent Period LoanDelinquentPeriod	P30D
CY2021	isbc	Accrual Of Income On Loans Discontinued Interest Or Principal Payments Accrual Period AccrualOfIncomeOnLoansDiscontinuedInterestOrPrincipalPaymentsAccrualPeriod	P90D
CY2021Q4	isbc	Loans Deferred LoansDeferred	279000000	USD
CY2021	isbc	Loans Impairment Analysis Minimum Commercial Real Estate Multi Family And Construction Loans Outstanding Balance LoansImpairmentAnalysisMinimumCommercialRealEstateMultiFamilyAndConstructionLoansOutstandingBalance	1000000	USD
CY2021Q4	isbc	Outstanding Minimum Balance Of Loans That Are Evaluated For Impairment Individually OutstandingMinimumBalanceOfLoansThatAreEvaluatedForImpairmentIndividually	1000000	USD
CY2021Q4	isbc	Bank Owned Life Insurance Carrying Value Consists Of Cash Surrender Value BankOwnedLifeInsuranceCarryingValueConsistsOfCashSurrenderValue	229400000	USD
CY2020Q4	isbc	Bank Owned Life Insurance Carrying Value Consists Of Cash Surrender Value BankOwnedLifeInsuranceCarryingValueConsistsOfCashSurrenderValue	223700000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	116200000	USD
CY2018Q4	isbc	Stock Repurchase Program Number Of Shares Authorized To Be Repurchased Percentage StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchasedPercentage	0.10
CY2018Q4	us-gaap	Stock Repurchase Program Number Of Shares Authorized To Be Repurchased StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased	28886780	shares
CY2021Q4	us-gaap	Stock Repurchase Program Remaining Number Of Shares Authorized To Be Repurchased StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased	12000202	shares
CY2021	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	975469	shares
CY2021	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	12100000	USD
CY2021	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	12.43
CY2020	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2377814	shares
CY2020	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	23900000	USD
CY2020	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	10.06
CY2019	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	39365145	shares
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	475900000	USD
CY2019	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	12.09
CY2021	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.56
CY2020	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.48
CY2019	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.44
CY2021Q4	isbc	Dividend Payout Ratio DividendPayoutRatio	0.42
CY2020Q4	isbc	Dividend Payout Ratio DividendPayoutRatio	0.51
CY2019Q4	isbc	Dividend Payout Ratio DividendPayoutRatio	0.59
CY2021Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	8200000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	36000000	USD
CY2021	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	356000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	256000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	150000	USD
CY2021	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	-248000	USD
CY2020	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	0	USD
CY2019	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	0	USD
CY2021	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	108000	USD
CY2020	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	256000	USD
CY2019	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	150000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	2373647000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	33368000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	13475000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	2393540000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	1867000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1593785000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss	2683322000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	75420000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	305000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	2758437000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	3264000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss	1247853000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	749657000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	11607000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	145278000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	1868000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	894935000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	13475000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	691151000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	9634000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	37355000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	1994000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	728506000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	11628000	USD
CY2021Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value MarketableSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	1440808000	USD
CY2021Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses MarketableSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses	21241000	USD
CY2021Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value MarketableSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	182633000	USD
CY2021Q4	isbc	Marketable Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses MarketableSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	3862000	USD
CY2021Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Fair Value MarketableSecuritiesContinuousUnrealizedLossPositionFairValue	1623441000	USD
CY2021Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Aggregate Losses MarketableSecuritiesContinuousUnrealizedLossPositionAggregateLosses	25103000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	192893000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	305000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	0	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	192893000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	305000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	121609000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1860000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	121609000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	1860000	USD
CY2020Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value MarketableSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	314502000	USD
CY2020Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Less Than12 Months Aggregate Losses MarketableSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses	2165000	USD
CY2020Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value MarketableSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	0	USD
CY2020Q4	isbc	Marketable Securities Continuous Unrealized Loss Position12 Months Or Longer Aggregate Losses MarketableSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0	USD
CY2020Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Fair Value MarketableSecuritiesContinuousUnrealizedLossPositionFairValue	314502000	USD
CY2020Q4	isbc	Marketable Securities Continuous Unrealized Loss Position Aggregate Losses MarketableSecuritiesContinuousUnrealizedLossPositionAggregateLosses	2165000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	1900000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Restricted HeldToMaturitySecuritiesRestricted	2070000000.00	USD
CY2021Q4	isbc	Debt Securities Held To Maturity Securities Restricted Fair Value DebtSecuritiesHeldToMaturitySecuritiesRestrictedFairValue	2110000000	USD
CY2021	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	356000	USD
CY2021	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	34000000	USD
CY2021	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	-248000	USD
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	8200000	USD
CY2021	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	398000	USD
CY2020	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	256000	USD
CY2020	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	0	USD
CY2020	us-gaap	Proceeds From Sale And Maturity Of Held To Maturity Securities ProceedsFromSaleAndMaturityOfHeldToMaturitySecurities	16500000	USD
CY2020	us-gaap	Held To Maturity Securities Sold Security Realized Gain Loss HeldToMaturitySecuritiesSoldSecurityRealizedGainLoss	124000	USD
CY2020	isbc	Principal Proceeds From Sale And Maturity Of Held To Maturity Securities PrincipalProceedsFromSaleAndMaturityOfHeldToMaturitySecurities	26000	USD
CY2019	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	150000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	399400000	USD
CY2019	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	5700000	USD
CY2019	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	0	USD
CY2018Q4	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Credit Losses On Debt Securities Held OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld	80595000	USD
CY2019	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Reductions Cash Flows OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsCashFlows	3530000	USD
CY2019	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Reductions Securities Sold OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsSecuritiesSold	0	USD
CY2019Q4	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Credit Losses On Debt Securities Held OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld	77065000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	22598047000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	20872755000	USD
CY2021Q4	isbc	Deferred Fees Premiums And Other Net DeferredFeesPremiumsAndOtherNet	-14754000	USD
CY2020Q4	isbc	Deferred Fees Premiums And Other Net DeferredFeesPremiumsAndOtherNet	-9318000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	240681000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	282986000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	22342612000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	20580451000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	6046374000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	2912837000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	2151672000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	2458659000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	1624525000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	5780879000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	1623101000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	22598047000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	3374318000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	2888650000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	3075527000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	2191782000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	2623693000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	5601930000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	1116855000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	20872755000	USD
CY2021Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	22598047000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	20872755000	USD
CY2021Q4	isbc	Financing Receivables Number Of Non Accrual Loans FinancingReceivablesNumberOfNonAccrualLoans	263	loan
CY2021Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	105184000	USD
CY2020Q4	isbc	Financing Receivables Number Of Non Accrual Loans FinancingReceivablesNumberOfNonAccrualLoans	311	loan
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	107125000	USD
CY2021	isbc	Interest Income On Non Accrual Loans InterestIncomeOnNonAccrualLoans	1000000	USD
CY2021Q4	isbc	Collateral Dependent Loans Receivable CollateralDependentLoansReceivable	74582000	USD
CY2020Q4	isbc	Collateral Dependent Loans Receivable CollateralDependentLoansReceivable	72046000	USD
CY2019	us-gaap	Direct Financing Lease Impairment Loss DirectFinancingLeaseImpairmentLoss	2600000	USD
CY2020	us-gaap	Direct Financing Lease Impairment Loss DirectFinancingLeaseImpairmentLoss	2200000	USD
CY2021	us-gaap	Direct Financing Lease Impairment Loss DirectFinancingLeaseImpairmentLoss	150000	USD
CY2021Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	USD
CY2021Q4	isbc	Loans Deferred LoansDeferred	279000000	USD
CY2021Q4	isbc	Financing Receivable Modifications Numberof Contracts Still Accruing FinancingReceivableModificationsNumberofContractsStillAccruing	44	loan
CY2021Q4	isbc	Financing Receivable Modifications Recorded Investment Still Accruing FinancingReceivableModificationsRecordedInvestmentStillAccruing	7565000	USD
CY2021Q4	isbc	Financing Receivable Modifications Number Of Contracts Nonaccrual FinancingReceivableModificationsNumberOfContractsNonaccrual	74	loan
CY2021Q4	isbc	Financing Receivable Modifications Recorded Investment Non Accrual FinancingReceivableModificationsRecordedInvestmentNonAccrual	53084000	USD
CY2021Q4	isbc	Financing Receivable Modifications Number Of Contracts At End Of Period FinancingReceivableModificationsNumberOfContractsAtEndOfPeriod	118	loan
CY2021Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	60649000	USD
CY2020Q4	isbc	Financing Receivable Modifications Numberof Contracts Still Accruing FinancingReceivableModificationsNumberofContractsStillAccruing	47	loan
CY2020Q4	isbc	Financing Receivable Modifications Recorded Investment Still Accruing FinancingReceivableModificationsRecordedInvestmentStillAccruing	9232000	USD
CY2020Q4	isbc	Financing Receivable Modifications Number Of Contracts Nonaccrual FinancingReceivableModificationsNumberOfContractsNonaccrual	89	loan
CY2020Q4	isbc	Financing Receivable Modifications Recorded Investment Non Accrual FinancingReceivableModificationsRecordedInvestmentNonAccrual	25265000	USD
CY2020Q4	isbc	Financing Receivable Modifications Number Of Contracts At End Of Period FinancingReceivableModificationsNumberOfContractsAtEndOfPeriod	136	loan
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	34497000	USD
CY2021	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2000000	USD
CY2020	isbc	Number Of Loans Granted Deferral Payment NumberOfLoansGrantedDeferralPayment	2	loan
CY2021	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-43843000	USD
CY2020	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	64890000	USD
CY2021	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-1397000	USD
CY2020	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	700000	USD
CY2021	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-3436000	USD
CY2020	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	4568000	USD
CY2021	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-48676000	USD
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	70158000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	282986000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	228120000	USD
CY2021	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	5064000	USD
CY2020	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	18388000	USD
CY2021	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5605000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	7735000	USD
CY2021	isbc	Financing Receivable Allowance For Credit Loss Write Off After Recovery Net FinancingReceivableAllowanceForCreditLossWriteOffAfterRecoveryNet	-541000	USD
CY2020	isbc	Financing Receivable Allowance For Credit Loss Write Off After Recovery Net FinancingReceivableAllowanceForCreditLossWriteOffAfterRecoveryNet	10653000	USD
CY2021	us-gaap	Financing Receivable Allowance For Credit Loss Purchased With Credit Deterioration Increase FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease	997000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Loss Purchased With Credit Deterioration Increase FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease	4180000	USD
CY2021	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-43843000	USD
CY2020	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	64890000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	240681000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	282986000	USD
CY2021Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	70300000	USD
CY2020Q4	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	69600000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	282986000	USD
CY2021	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	5064000	USD
CY2021	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	5605000	USD
CY2021	us-gaap	Financing Receivable Allowance For Credit Loss Purchased With Credit Deterioration Increase FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease	997000	USD
CY2021	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-43843000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	240681000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	228120000	USD
CY2020	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	18388000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	7735000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Loss Purchased With Credit Deterioration Increase FinancingReceivableAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease	4180000	USD
CY2020	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	64890000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	282986000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	3264000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2021	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-1397000	USD
CY2020	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	700000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	1867000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	3264000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	3264000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2021	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-1397000	USD
CY2020	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	700000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	1867000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	3264000	USD
CY2021Q4	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	5100000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	5200000	USD
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0240
CY2020Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	17667000	USD
CY2019Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	425000	USD
CY2021	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-3436000	USD
CY2020	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	4568000	USD
CY2021Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	14231000	USD
CY2020Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	17667000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	288545000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	297279000	USD
CY2021Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	159257000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	157616000	USD
CY2021Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	129288000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	139663000	USD
CY2021	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	21600000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	21300000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	19600000	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	50000000	USD
CY2020	isbc	Sale And Leaseback Transaction Gain Loss Gross SaleAndLeasebackTransactionGainLossGross	23100000	USD
CY2020	us-gaap	Sale And Leaseback Transaction Gain Loss Net SaleAndLeasebackTransactionGainLossNet	16700000	USD
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	199603000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	199981000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	212678000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	212559000	USD
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P8Y6M
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P9Y4M24D
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0249
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	29986000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	26242000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	25245000	USD
CY2021	us-gaap	Short Term Lease Cost ShortTermLeaseCost	827000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	460000	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	306000	USD
CY2021	us-gaap	Variable Lease Cost VariableLeaseCost	2000	USD
CY2020	us-gaap	Variable Lease Cost VariableLeaseCost	2000	USD
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	1000	USD
CY2021	us-gaap	Sublease Income SubleaseIncome	209000	USD
CY2020	us-gaap	Sublease Income SubleaseIncome	253000	USD
CY2019	us-gaap	Sublease Income SubleaseIncome	268000	USD
CY2021	us-gaap	Operating Lease Payments OperatingLeasePayments	29540000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	24973000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	24497000	USD
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	25683000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	46758000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	2996000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	30709000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	29746000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	29440000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	28786000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	24349000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	92697000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	235727000	USD
CY2021Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	23049000	USD
CY2021Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	212678000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	41772000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	25664000	USD
CY2021Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	798000	USD
CY2021Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	813000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	15765000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	15098000	USD
CY2021Q4	us-gaap	Goodwill Goodwill	116228000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	94535000	USD
CY2021Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	131993000	USD
CY2020Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	109633000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	42195000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	26360000	USD
CY2021Q4	isbc	Finite Intangible Assets Valuation Allowance FiniteIntangibleAssetsValuationAllowance	70000	USD
CY2021Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	15765000	USD
CY2021	us-gaap	Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Discount Rate ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValueDiscountRate	0.1131
CY2020Q4	isbc	Finite Intangible Assets Valuation Allowance FiniteIntangibleAssetsValuationAllowance	1010000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	15098000	USD
CY2021Q4	us-gaap	Continuing Involvement With Transferred Financial Assets Principal Amount Outstanding ContinuingInvolvementWithTransferredFinancialAssetsPrincipalAmountOutstanding	1330000000	USD
CY2020Q4	us-gaap	Continuing Involvement With Transferred Financial Assets Principal Amount Outstanding ContinuingInvolvementWithTransferredFinancialAssetsPrincipalAmountOutstanding	1690000000	USD
CY2021Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	10800000	USD
CY2020Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	11200000	USD
CY2021	us-gaap	Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Prepayment Speed ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValuePrepaymentSpeed	0.1278
CY2021	us-gaap	Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Weighted Average Life1 ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValueWeightedAverageLife1	P5Y6M
CY2021Q4	us-gaap	Noninterest Bearing Domestic Deposit Checking NoninterestBearingDomesticDepositChecking	4658319000	USD
CY2021Q4	isbc	Percentage Of Non Interest Bearing Domestic Deposits To Deposits Checking PercentageOfNonInterestBearingDomesticDepositsToDepositsChecking	0.2237
CY2020Q4	us-gaap	Noninterest Bearing Domestic Deposit Checking NoninterestBearingDomesticDepositChecking	3663073000	USD
CY2020Q4	isbc	Percentage Of Non Interest Bearing Domestic Deposits To Deposits Checking PercentageOfNonInterestBearingDomesticDepositsToDepositsChecking	0.1876
CY2021Q4	us-gaap	Weighted Average Rate Domestic Deposit Checking WeightedAverageRateDomesticDepositChecking	0.0036
CY2021Q4	isbc	Deposits Checking Account DepositsCheckingAccount	7270634000	USD
CY2021Q4	isbc	Percentage Of Domestic Deposits To Deposits Checking PercentageOfDomesticDepositsToDepositsChecking	0.3491
CY2020Q4	us-gaap	Weighted Average Rate Domestic Deposit Checking WeightedAverageRateDomesticDepositChecking	0.0049
CY2020Q4	isbc	Deposits Checking Account DepositsCheckingAccount	6043393000	USD
CY2020Q4	isbc	Percentage Of Domestic Deposits To Deposits Checking PercentageOfDomesticDepositsToDepositsChecking	0.3095
CY2021Q4	us-gaap	Weighted Average Rate Domestic Deposit Money Market WeightedAverageRateDomesticDepositMoneyMarket	0.0031
CY2021Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	4757567000	USD
CY2021Q4	isbc	Percentage Of Domestic Deposits To Deposits Money Market PercentageOfDomesticDepositsToDepositsMoneyMarket	0.2285
CY2020Q4	us-gaap	Weighted Average Rate Domestic Deposit Money Market WeightedAverageRateDomesticDepositMoneyMarket	0.0042
CY2020Q4	us-gaap	Deposits Money Market Deposits DepositsMoneyMarketDeposits	5037327000	USD
CY2020Q4	isbc	Percentage Of Domestic Deposits To Deposits Money Market PercentageOfDomesticDepositsToDepositsMoneyMarket	0.2580
CY2021Q4	us-gaap	Weighted Average Rate Domestic Deposit Savings WeightedAverageRateDomesticDepositSavings	0.0024
CY2021Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2043152000	USD
CY2021Q4	isbc	Percentage Of Domestic Deposits To Deposits Savings PercentageOfDomesticDepositsToDepositsSavings	0.0981
CY2020Q4	us-gaap	Weighted Average Rate Domestic Deposit Savings WeightedAverageRateDomesticDepositSavings	0.0048
CY2020Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	2063447000	USD
CY2020Q4	isbc	Percentage Of Domestic Deposits To Deposits Savings PercentageOfDomesticDepositsToDepositsSavings	0.1057
CY2021Q4	us-gaap	Weighted Average Rate Domestic Deposit Certificates Of Deposit WeightedAverageRateDomesticDepositCertificatesOfDeposit	0.0043
CY2021Q4	us-gaap	Interest Bearing Domestic Deposit Certificates Of Deposits InterestBearingDomesticDepositCertificatesOfDeposits	2094966000	USD
CY2021Q4	isbc	Percentage Of Domestic Deposits To Deposits Certificates Of Deposit PercentageOfDomesticDepositsToDepositsCertificatesOfDeposit	0.1006
CY2020Q4	us-gaap	Weighted Average Rate Domestic Deposit Certificates Of Deposit WeightedAverageRateDomesticDepositCertificatesOfDeposit	0.0097
CY2020Q4	us-gaap	Interest Bearing Domestic Deposit Certificates Of Deposits InterestBearingDomesticDepositCertificatesOfDeposits	2718179000	USD
CY2020Q4	isbc	Percentage Of Domestic Deposits To Deposits Certificates Of Deposit PercentageOfDomesticDepositsToDepositsCertificatesOfDeposit	0.1392
CY2021Q4	us-gaap	Weighted Average Rate Domestic Deposit WeightedAverageRateDomesticDeposit	0.0026
CY2021Q4	us-gaap	Deposits Domestic DepositsDomestic	20824638000	USD
CY2021Q4	isbc	Percentage Of Domestic Deposits To Deposits PercentageOfDomesticDepositsToDeposits	1.0000
CY2020Q4	us-gaap	Weighted Average Rate Domestic Deposit WeightedAverageRateDomesticDeposit	0.0045
CY2020Q4	us-gaap	Deposits Domestic DepositsDomestic	19525419000	USD
CY2020Q4	isbc	Percentage Of Domestic Deposits To Deposits PercentageOfDomesticDepositsToDeposits	1.0000
CY2021Q4	us-gaap	Deposit Liability Uninsured DepositLiabilityUninsured	10770000000	USD
CY2020Q4	us-gaap	Deposit Liability Uninsured DepositLiabilityUninsured	9510000000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	1788084000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	2386850000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	178287000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	271302000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	92208000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	31893000	USD
CY2021Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	12476000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	15016000	USD
CY2021Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	23911000	USD
CY2020Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	13118000	USD
CY2021Q4	us-gaap	Time Deposits TimeDeposits	2094966000	USD
CY2020Q4	us-gaap	Time Deposits TimeDeposits	2718179000	USD
CY2021	us-gaap	Interest Expense Domestic Deposit Liabilities Checking InterestExpenseDomesticDepositLiabilitiesChecking	27488000	USD
CY2020	us-gaap	Interest Expense Domestic Deposit Liabilities Checking InterestExpenseDomesticDepositLiabilitiesChecking	42014000	USD
CY2019	us-gaap	Interest Expense Domestic Deposit Liabilities Checking InterestExpenseDomesticDepositLiabilitiesChecking	84698000	USD
CY2021	us-gaap	Interest Expense Domestic Deposit Liabilities Money Market InterestExpenseDomesticDepositLiabilitiesMoneyMarket	20508000	USD
CY2020	us-gaap	Interest Expense Domestic Deposit Liabilities Money Market InterestExpenseDomesticDepositLiabilitiesMoneyMarket	42568000	USD
CY2019	us-gaap	Interest Expense Domestic Deposit Liabilities Money Market InterestExpenseDomesticDepositLiabilitiesMoneyMarket	60896000	USD
CY2021	us-gaap	Interest Expense Domestic Deposit Liabilities Savings InterestExpenseDomesticDepositLiabilitiesSavings	5591000	USD
CY2020	us-gaap	Interest Expense Domestic Deposit Liabilities Savings InterestExpenseDomesticDepositLiabilitiesSavings	12056000	USD
CY2019	us-gaap	Interest Expense Domestic Deposit Liabilities Savings InterestExpenseDomesticDepositLiabilitiesSavings	17148000	USD
CY2021	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	14318000	USD
CY2020	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	58951000	USD
CY2019	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	99115000	USD
CY2021	us-gaap	Interest Expense Deposits InterestExpenseDeposits	67905000	USD
CY2020	us-gaap	Interest Expense Deposits InterestExpenseDeposits	155589000	USD
CY2019	us-gaap	Interest Expense Deposits InterestExpenseDeposits	261857000	USD
CY2021Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	449117000	USD
CY2021Q4	isbc	Securities Sold Under Agreements To Repurchase Weighted Average Interest Rate SecuritiesSoldUnderAgreementsToRepurchaseWeightedAverageInterestRate	0.0197
CY2020Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	448514000	USD
CY2020Q4	isbc	Securities Sold Under Agreements To Repurchase Weighted Average Interest Rate SecuritiesSoldUnderAgreementsToRepurchaseWeightedAverageInterestRate	0.0197
CY2021Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	3071419000	USD
CY2021Q4	us-gaap	Federal Home Loan Bank Advances Weighted Average Interest Rate FederalHomeLoanBankAdvancesWeightedAverageInterestRate	0.0074
CY2020Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	2662574000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Weighted Average Interest Rate FederalHomeLoanBankAdvancesWeightedAverageInterestRate	0.0120
CY2021Q4	us-gaap	Subordinated Debt SubordinatedDebt	14502000	USD
CY2021Q4	isbc	Subordinated Debt Weighted Average Interest Rate SubordinatedDebtWeightedAverageInterestRate	0.0650
CY2020Q4	us-gaap	Subordinated Debt SubordinatedDebt	14702000	USD
CY2020Q4	isbc	Subordinated Debt Weighted Average Interest Rate SubordinatedDebtWeightedAverageInterestRate	0.0650
CY2021Q4	us-gaap	Other Long Term Debt OtherLongTermDebt	0	USD
CY2021Q4	isbc	Other Debt Weighted Average Interest Rate OtherDebtWeightedAverageInterestRate	0
CY2020Q4	us-gaap	Other Long Term Debt OtherLongTermDebt	170000000	USD
CY2020Q4	isbc	Other Debt Weighted Average Interest Rate OtherDebtWeightedAverageInterestRate	0.0013
CY2021Q4	isbc	Borrowed Funds Other BorrowedFundsOther	3085921000	USD
CY2021Q4	isbc	Borrowed Funds Other Weighted Average Interest Rate BorrowedFundsOtherWeightedAverageInterestRate	0.0077
CY2020Q4	isbc	Borrowed Funds Other BorrowedFundsOther	2847276000	USD
CY2020Q4	isbc	Borrowed Funds Other Weighted Average Interest Rate BorrowedFundsOtherWeightedAverageInterestRate	0.0117
CY2021Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	3535038000	USD
CY2021Q4	us-gaap	Debt Weighted Average Interest Rate DebtWeightedAverageInterestRate	0.0092
CY2020Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	3295790000	USD
CY2020Q4	us-gaap	Debt Weighted Average Interest Rate DebtWeightedAverageInterestRate	0.0128
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	2350000000	USD
CY2021Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year One BorrowedFundsWeightedAverageInterestRateMaturitiesYearOne	0.0036
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	1513000000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	91248000	USD
CY2020Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year One BorrowedFundsWeightedAverageInterestRateMaturitiesYearOne	0.0033
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	497448000	USD
CY2021Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year Two BorrowedFundsWeightedAverageInterestRateMaturitiesYearTwo	0.0212
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	574741000	USD
CY2020Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year Two BorrowedFundsWeightedAverageInterestRateMaturitiesYearTwo	0.0215
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	673088000	USD
CY2021Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year Three BorrowedFundsWeightedAverageInterestRateMaturitiesYearThree	0.0190
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	520989000	USD
CY2020Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year Three BorrowedFundsWeightedAverageInterestRateMaturitiesYearThree	0.0210
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	0	USD
CY2021Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year Four BorrowedFundsWeightedAverageInterestRateMaturitiesYearFour	0
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	672358000	USD
CY2020Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year Four BorrowedFundsWeightedAverageInterestRateMaturitiesYearFour	0.0190
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	0	USD
CY2021Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year Five BorrowedFundsWeightedAverageInterestRateMaturitiesYearFive	0
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	0	USD
CY2020Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year Five BorrowedFundsWeightedAverageInterestRateMaturitiesYearFive	0
CY2021Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	14502000	USD
CY2021Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year After Five BorrowedFundsWeightedAverageInterestRateMaturitiesYearAfterFive	0.0650
CY2020Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	14702000	USD
CY2020Q4	isbc	Borrowed Funds Weighted Average Interest Rate Maturities Year After Five BorrowedFundsWeightedAverageInterestRateMaturitiesYearAfterFive	0.0650
CY2021Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	3535038000	USD
CY2021Q4	us-gaap	Debt Weighted Average Interest Rate DebtWeightedAverageInterestRate	0.0092
CY2020Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	3295790000	USD
CY2020Q4	us-gaap	Debt Weighted Average Interest Rate DebtWeightedAverageInterestRate	0.0128
CY2021Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Securities For Repurchase Agreements PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements	474621000	USD
CY2020Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Securities For Repurchase Agreements PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements	471506000	USD
CY2021Q4	us-gaap	Securities Sold Under Agreements To Repurchase Fair Value Of Collateral SecuritiesSoldUnderAgreementsToRepurchaseFairValueOfCollateral	488896000	USD
CY2020Q4	us-gaap	Securities Sold Under Agreements To Repurchase Fair Value Of Collateral SecuritiesSoldUnderAgreementsToRepurchaseFairValueOfCollateral	494160000	USD
CY2019	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	369000000	USD
CY2021	isbc	Maximum Month End Balance Of Repurchase Agreements MaximumMonthEndBalanceOfRepurchaseAgreements	449100000	USD
CY2020	isbc	Maximum Month End Balance Of Repurchase Agreements MaximumMonthEndBalanceOfRepurchaseAgreements	548000000	USD
CY2019	isbc	Maximum Month End Balance Of Repurchase Agreements MaximumMonthEndBalanceOfRepurchaseAgreements	447900000	USD
CY2021	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	448800000	USD
CY2020	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Balance Of Agreements Outstanding FederalHomeLoanBankAdvancesActivityForYearAverageBalanceOfAgreementsOutstanding	451700000	USD
CY2021	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Interest Rate For Year FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear	0.0214
CY2020	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Interest Rate For Year FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear	0.0217
CY2019	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Interest Rate For Year FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear	0.0245
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	71775000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	82039000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	32881000	USD
CY2021	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	28926000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	27112000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	12743000	USD
CY2021	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	100701000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	109151000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	45624000	USD
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	10955000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-25104000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	28784000	USD
CY2021	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	3424000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-9086000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	16840000	USD
CY2021	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	14379000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-34190000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	45624000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	115080000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	74961000	USD
CY2021	isbc	Effective Income Tax Rate Reconciliation Nondeductible Expense Fdic Premiums Amount EffectiveIncomeTaxRateReconciliationNondeductibleExpenseFDICPremiumsAmount	1132000	USD
CY2021	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	89967000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	62273000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	60214000	USD
CY2021	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	27637000	USD
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	12790000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	19075000	USD
CY2021	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-1240000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	7823000	USD
CY2021	isbc	Effective Income Tax Rate Reconciliation Tax Exempt Interest Income Amount EffectiveIncomeTaxRateReconciliationTaxExemptInterestIncomeAmount	2410000	USD
CY2020	isbc	Effective Income Tax Rate Reconciliation Tax Exempt Interest Income Amount EffectiveIncomeTaxRateReconciliationTaxExemptInterestIncomeAmount	2399000	USD
CY2019	isbc	Effective Income Tax Rate Reconciliation Tax Exempt Interest Income Amount EffectiveIncomeTaxRateReconciliationTaxExemptInterestIncomeAmount	1519000	USD
CY2020	isbc	Effective Income Tax Rate Reconciliation Nondeductible Expense Fdic Premiums Amount EffectiveIncomeTaxRateReconciliationNondeductibleExpenseFDICPremiumsAmount	1169000	USD
CY2019	isbc	Effective Income Tax Rate Reconciliation Nondeductible Expense Fdic Premiums Amount EffectiveIncomeTaxRateReconciliationNondeductibleExpenseFDICPremiumsAmount	1229000	USD
CY2021	isbc	Effective Income Tax Rate Reconciliation Bank Owned Life Insurance EffectiveIncomeTaxRateReconciliationBankOwnedLifeInsurance	-1375000	USD
CY2020	isbc	Effective Income Tax Rate Reconciliation Bank Owned Life Insurance EffectiveIncomeTaxRateReconciliationBankOwnedLifeInsurance	-1394000	USD
CY2019	isbc	Effective Income Tax Rate Reconciliation Bank Owned Life Insurance EffectiveIncomeTaxRateReconciliationBankOwnedLifeInsurance	-1374000	USD
CY2021	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	677000	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	1610000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Credits IncomeTaxReconciliationTaxCredits	0	USD
CY2021	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	2046000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	4132000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	5800000	USD
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	115080000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	74961000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	91248000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	27716000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	2002000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	29754000	USD
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	412000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	480000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	3926000	USD
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CY2021Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	2997000	USD
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CY2021	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	186000	USD
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CY2021	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	32114000	USD
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Files In Submission

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Investors Bancorp, Inc.

2022 Q1 Form 10-K Financial Statement

#000159401222000022 Filed on March 01, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission