Document and Entity Information [Abstract] Document and Entity Information Statement [Table] Statement [Line Items] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Entity Common Stock, Shares Outstanding Entity Voluntary Filers Entity Current Reporting Status Entity Well-known Seasoned Issuer Entity Public Float Consolidated Statements of Financial Condition Assets [Abstract] Assets Cash and Due from Banks Cash and amounts due from depository institutions Cash and Due from Banks, Total Interest-bearing Deposits in Banks and Other Financial Institutions Interest-bearing deposits in other banks Cash and Cash Equivalents, at Carrying Value Cash and Cash Equivalents - Ending Cash and Cash Equivalents - Beginning Cash and Cash Equivalents Cash and Cash Equivalents Securities available for sale (amortized cost $30,441 and $30,960) Securities available for sale (amortized cost; 2012 $14,613; 2011 $46,145) Carrying Value Mortgage-backed securities available for sale (amortized cost 2011 $1,771 2010 $3,163) Held-to-maturity Securities Securities held to maturity (estimated fair value; 2012 $34,838; 2011 $107,052) Held-to-maturity Securities, Total Carrying Value Loans and Leases Receivable, Net of Deferred Income Loans receivable, including net yield adjustments 2012 $1,654; 2011 $1,021 Loans Receivable, Net of Yield Adjustments, Total Loans receivable Less allowance for loan losses Less allowance for loan losses Balance - ending Balance - beginning Allowance Loans and Leases Receivable, Allowance, Total Add: General valuation allowance for loan losses Net Loans Receivable Net Loans Receivable Mortgage-backed securities available for sale (amortized cost $815,706 and $673,414) Mortgage-backed securities available for sale (amortized cost; 2012 $1,188,373; 2011 $1,032,407) Carrying Value Mortgage-backed securities available for sale This element represents the portion of the balance sheet assertion valued at amortized cost. This item represents securitized, pay-through debt securities collateralized by real estate mortgage loans (mortgages) as of the balance sheet date which have been categorized as held-to-maturity. The held-to-maturity category is for those securities that the Entity has the positive intent and ability to hold until maturity. Mortgage Backed Securities Held To Maturity, Amortized Cost Mortgage-backed securities held to maturity (estimated fair value; 2012 $1,159; 2011 $1,416) Carrying Value Premises and equipment Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance Premises and equipment Premises and equipment, Net, Total Federal Home Loan Bank Stock Federal Home Loan Bank of New York stock Interest receivable Goodwill Less: Goodwill Goodwill, Ending Balance Goodwill, Beginning Balance Less: Goodwill Goodwill, Total Bank owned life insurance Other assets Other Assets, Total Assets Total Assets Total Assets Liabilities and Stockholders' Equity Liabilities [Abstract] Liabilities Noninterest-bearing Deposit Liabilities, Domestic Deposits: Non-interest bearing Noninterest-bearing Deposit Liabilities, Domestic, Total Non-interest bearing demand: Amount Interest-bearing Deposit Liabilities, Domestic Deposits: Interest-bearing Interest-bearing Deposit Liabilities, Domestic, Total Total Deposits Total Deposits Federal Home Loan Bank advances and other short term borrowings. Borrowings Advance Payments by Borrowers for Taxes and Insurance Advance payments by borrowers for taxes Deferred income tax liabilities, net Deferred income tax liabilities, net Net deferred income tax liability Other liabilities Other Liabilities, Total Liabilities Total Liabilities Stockholders' Equity Attributable to Parent [Abstract] Stockholders' Equity Preferred Stock, Value, Issued Preferred Stock, Value, Issued, Ending Balance Preferred Stock, Value, Issued, Beginning Balance Preferred stock, $0.10 par value; 25,000,000 shares authorized; none issued and outstanding Preferred Stock, Value, Issued, Total Common Stock, Value, Issued Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common stock $0.10 par value, 75,000,000 shares authorized; 72,737,500 shares issued; 2012 66,936,040 and 2011 67,851,077 shares outstanding, respectively Common Stock, Value, Issued, Total Additional Paid in Capital, Common Stock Additional Paid in Capital, Common Stock, Ending Balance Additional Paid in Capital, Common Stock, Beginning Balance Paid-in capital Retained earnings Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit), Beginning Balance Retained Earnings (Accumulated Deficit), Total Unearned ESOP Shares Unearned Employee Stock Ownership Plan shares; 2012 678,878; 2011 824,352 shares Unearned Employee Stock Ownership Plan shares; 715,247 shares and 824,352 shares, respectively Treasury stock, at cost; 4,762,023 shares and 4,393,223 shares, respectively Treasury stock, at cost; 2012 5,801,460; 2011 4,886,423 shares Treasury Stock, Value, Ending Balance Treasury Stock, Value, Beginning Balance Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance Accumulated other comprehensive income Accumulated other comprehensive income Stockholders' Equity Attributable to Parent Balance (in value) Balance (in value) Stockholders' equity Total Stockholders' Equity GAAP capital: Consolidated capital Liabilities and Equity Total Liabilities and Stockholders' Equity Total Liabilities and Stockholders' Equity Securities available for sale, amortized cost Available-for-sale Securities, Amortized Cost Basis, Total Amortized Cost Securities held to maturity (estimated fair value $232,063 and $256,914) Securities held to maturity, estimated fair value Estimated Fair Value Estimated Fair Value Loans and Leases Receivable, Deferred Income Loans receivable, unamortized yield adjustments Loans and Leases Receivable, Deferred Income, Total Mortgage-backed securities available for sale amortized cost Mortgage-backed securities available for sale amortized cost Mortgage-backed securities available for sale, amortized cost Amortized Cost Mortgage-backed securities held to maturity (estimated fair value $1,701 and $1,754) Mortgage-backed securities held to maturity (estimated fair value $1,227 and $1,416) Estimated Fair Value Mortgage-backed securities held to maturity Preferred stock, par value Preferred stock, shares authorized Preferred stock, shares issued Preferred Stock, Shares Issued, Total Preferred stock, shares outstanding Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Common stock, par value Common stock, shares authorized Common stock, shares issued Common Stock, Shares, Issued, Total Common stock, shares outstanding Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Employee Stock Ownership Plan (ESOP), Number of Suspense Shares Unearned shares Unearned shares Treasury stock, shares Treasury Stock, Shares, Ending Balance Treasury Stock, Shares, Beginning Balance Consolidated Statements of Income Interest Income (Expense), Net [Abstract] Interest Income Loans Interest and Fee Income, Loans and Leases, Total Mortgage-backed securities Securities: Taxable Tax-exempt Other interest-earning assets Total Interest Income Interest income Total Interest Income Interest Expense [Abstract] Interest Expense Deposits Interest Expense on Deposits Interest Expense, Deposits, Total Interest Expense, Borrowings Borrowings Interest Expense, Borrowings, Total Interest Expense Interest expense Total Interest Expense Interest Income (Expense), Net Net Interest Income Net Interest Income Net interest income Provision for Loan Losses Provision for loan losses Provision for Loan and Lease Losses, Total Provisions charged to operations Net Interest Income after Provision for Loan Losses Net Interest Income after Provision for Loan Losses Non-Interest Income Fees and service charges Fees and Commissions, Total Gain (Loss) on Sale of Debt Investments Realized loss on sale of mortgage-backed securities held to maturity Realized loss on sale of mortgage-backed securities held to maturity Gain on sale of securities Other than Temporary Impairment Losses, Investments [Abstract] Other-than-temporary security impairment: Other than Temporary Impairment Losses, Investments Total Total Other than Temporary Impairment Losses, Investments, Total Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income (Loss), before Tax, Including Portion Attributable to Noncontrolling Interest Less: Portion recognized in other comprehensive income Less: Portion recognized in other comprehensive income Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income (Loss), before Tax, Including Portion Attributable to Noncontrolling Interest, Total Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net Portion recognized in earnings Portion recognized in earnings Gain (Loss) on Sales of Loans, Net Realized gain on sale of loans Realized gain on sale of loans Gain (Loss) on Sales of Loans, Net, Total Gain on sale of loans Gains (Losses) on Sales of Other Real Estate Loss on sale and write down of real estate owned Increase in cash surrender value of bank owned life insurance Increase in cash surrender value of bank owned life insurance Income from bank owned life insurance Fees and Commissions, Other Electronic banking fees and charges Miscellaneous Total Non-Interest Income Non-interest income Total Non-Interest Income Non-Interest Expenses Labor and Related Expense Salaries and employee benefits Salaries and employee benefits Net occupancy expense of premises Equipment Expense Equipment and systems Marketing and Advertising Expense Advertising Advertising and marketing Federal deposit insurance premium Noninterest Expense Directors Fees Directors' compensation Business Combination, Integration Related Costs Merger-related expenses Other Noninterest Expense Miscellaneous Total Non-Interest Expenses Non-interest expenses Total Non-Interest Expenses Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income Before Income Taxes Income Before Income Taxes Income Tax Expense (Benefit) Income Taxes Income Taxes Income tax (benefit) expense Net income Income (Numerator): Net income Net Income Net Income Net Income per Common Share (EPS) [Abstract] Net Income per Common Share (EPS) Earnings Per Share, Basic and Diluted Basic and Diluted Earnings Per Share, Basic and Diluted, Total Net income per common share: Basic and diluted Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted Average Number of Common Shares Outstanding: Weighted Average Number of Shares Outstanding, Basic and Diluted Basic and Diluted Weighted Average Number of Common Shares Outstanding: Basic and diluted Consolidated Statements of Changes in Stockholders' Equity Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Parent [Member] Parent [Member] Common Stock [Member] Common Stock [Member] Additional Paid In Capital [Member] Paid-In Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Unearned ESOP Shares [Member] Unearned Esop Shares [Member] Unearned ESOP Shares [Member] Treasury Stock [Member] Treasury Stock [Member] Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income (Loss) [Member] Balance, Shares Balance (in shares) Balance (in shares) Comprehensive income: Comprehensive income (loss): Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax Realized gain (loss) on securities available for sale, net of income tax Unrealized gain (loss) on securities available for sale, net of deferred income tax expense (benefit) Unrealized gain (loss) on securities available for sale, net of deferred income tax expense (benefit) Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Non-credit related other-than-temporary impairment on securities held to maturity sold, net of deferred income tax Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total Benefit plans, net of deferred income tax benefit Benefit plans, net of deferred income tax expense Benefit plans, net of deferred income tax benefit Comprehensive Income (Loss), Net of Tax, Attributable to Parent Total comprehensive income (loss) Other comprehensive income (loss) Amortization of ESOP Award ESOP shares committed to be released Cash dividends used to pay down ESOP loan. Dividends contributed for payment of ESOP loan Repayment of loan to ESOP Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Stock option expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Total Treasury stock purchases (in shares) Treasury stock purchases (in value) Treasury stock purchases (in value) Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition Restricted stock plan shares earned Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Tax effect from stock based compensation Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net, Total Cash dividends declared ($0.05/ public share) Cash dividends declared Cash dividends declared Cash dividend to Kearny MHC Cash dividend to Kearny MHC Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax Realized gain on securities available for sale, Tax Unrealized loss on securities available for sale, tax Unrealized gain on securities available for sale, Tax Deferred tax expense (benefit), Unrealized gain on securities available for sale Non-credit related other-than-temporary impairment losses on securities held to maturity, tax Non-credit related other-than-temporary impairment on securities held to maturity sold, Deferred Tax Deferred tax benefit, Non-credit related other-than-temporary impairment losses on securities held to maturity Deferred tax expense, Benefit plans Benefit plan, Deferred Tax Other Comprehensive Income, Defined Benefit Plans, Tax, Total Employee Stock Ownership Plan (ESOP), Shares Contributed to ESOP ESOP shares committed to be released, shares Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Restricted stock plan shares earned, shares Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures, Total Dividends Declared Per Common Share (Excluding dividends waived by Kearny MHC) Cash dividends declared, price per public share Dividends Declared Per Common Share Consolidated Statements of Cash Flows Net Cash Provided by (Used in) Operating Activities [Abstract] Cash Flows from Operating Activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Depreciation, Nonproduction Depreciation and amortization of premises and equipment The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method. Also includes the component of interest expense representing the noncash expenses charged against earnings in the period to allocated debt discount and premium, and the costs to issue debt and obtain financing over the related debt instruments. Net amortization of premiums, discounts and loan fees and costs Deferred Income Tax Expense (Benefit) Deferred income taxes Deferred tax (benefit) expense: Total Amortization of intangible assets Amortization Amortization of Intangible Assets, Total Defined Benefit Plan, Amortization of Gains (Losses) Amortization of benefit plans' unrecognized net loss Amortization of net gain / loss Available-for-sale Securities, Gross Realized Gain (Loss) Realized gain on sale of securities available for sale Available-for-sale Securities, Gross Realized Gain (Loss), Total Held-to-maturity Securities, Sold Security, Realized Gain (Loss), Excluding Other than Temporary Impairments Realized loss on sale of mortgage-backed securities held to maturity Proceeds from Sale of Loans Receivable Proceeds from sale of loans Other than Temporary Impairment Losses, Investments, Available-for-sale Securities Loss on other-than-temporary impairment of securities Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Total Gain (Loss) on Disposition of Property Realized loss on disposition of premises and equipment Gain (Loss) on Disposition of Property, Total Share-based Compensation ESOP, stock option plan and restricted stock plan expenses ESOP, stock option plan and restricted stock plan expenses Share-based Compensation, Total The non-cash write down of real estate owned. Loss on write-down and sales of real estate owned Loss (gain) on sale and write down of real estate owned Decrease in interest receivable Decrease (increase) in interest receivable Decrease (increase) in interest receivable Increase (Decrease) in Interest and Dividends Receivable, Total Increase (Decrease) in Other Operating Assets Decrease (increase) in other assets Decrease (increase) in other assets Decrease in other assets Increase (Decrease) in Other Operating Assets, Total Decrease (increase) in other assets Increase (Decrease) in Interest Payable, Net (Decrease) increase in interest payable Decrease in interest payable Increase (Decrease) in Other Operating Liabilities Increase(decrease) in other liabilities Increase (Decrease) in Other Operating Liabilities, Total Increase (decrease) in other liabilities Net Cash Provided by (Used in) Operating Activities Net Cash Provided by Operating Activities Net Cash Provided by Operating Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Cash Flows from Investing Activities: Proceeds from Sale of Available-for-sale Securities Proceeds from sales of securities available for sale Proceeds from Sale of Available-for-sale Securities, Total The cash inflow associated with maturities (principal being due) and calls (requests of early payments) on securities not classified as either held-to-maturity securities or trading securities which are classified as available-for-sale securities. Proceeds from calls and maturities of securities available for sale The cash inflow associated with repayments on securities not classified as either held-to-maturity securities or trading securities which are classified as available-for-sale securities. Proceeds from repayments of securities available for sale Payments to Acquire Held-to-maturity Securities Purchase of securities held to maturity Purchase of securities held to maturity The cash inflow associated with the maturities and calls (requests for early payments) of debt securities designated as held-to-maturity. Proceeds from calls and maturities of securities held to maturity The cash inflow associated with the repayments of debt securities designated as held-to-maturity. Proceeds from repayments of securities held to maturity Payments to Acquire Loans and Leases Held-for-investment Purchase of loans Purchase of loans Payments to Acquire Loans and Leases Held-for-investment, Total Payments for (Proceeds from) Loans and Leases Net decrease in loans receivable Net decrease in loans receivable Payments for (Proceeds from) Loans and Leases, Total Proceeds from Sale of Other Real Estate Proceeds from sale of real estate owned Proceeds from insurance claim on REO Proceeds from insurance claim on REO Proceeds from insurance claim on real estate owned Purchases of mortgage-backed securities available for sale Purchases of mortgage-backed securities available for sale Principal repayments on mortgage-backed securities available for sale Principal repayments on mortgage-backed securities available for sale Proceeds from Sale of Mortgage Backed Securities (MBS) categorized as Available-for-sale Proceeds from sale of mortgage-backed securities available for sale Principal Repayments On Mortgage Backed Securities Held To Maturity Principal Repayments On Mortgage Backed Securities Held To Maturity Principal repayments on mortgage-backed securities held to maturity The cash inflow from the sale of securities issued by a governmental agency or corporation (for example, GNMA or FHLMC) or by private issuers (for example, banks and mortgage banking enterprises) secured by and repaid from underlying mortgages, which were designated as held to maturity when acquired. Proceeds from sale of mortgage-backed securities held to maturity Payments to Acquire Property, Plant, and Equipment Additions to premises and equipment Additions to premises and equipment Payments to Acquire Property, Plant, and Equipment, Total Proceeds from Insurance Settlement, Investing Activities Proceeds from cash settlement of premises and equipment Payments to Acquire Life Insurance Policies Purchase of bank owned life insurance Purchase of bank owned life insurance The cash outflow associated with the acquistion of the Federal Home Loan Bank (equity interest in the FHLB) stock during the period. PurchasesOfFederalHomeLoanBankFhlbStock Purchases of FHLB stock The cash inflow associated with the redemption of FHLB stock. Redemption of FHLB stock Redemptions of FHLB stock Payments to Acquire Businesses, Net of Cash Acquired Cash paid in merger, net of cash acquired Cash paid in merger, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired, Total Net Cash Provided by (Used in) Investing Activities Net Cash Provided by Investing Activities Net Cash Used in Investing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Cash Flows from Financing Activities: Increase (Decrease) in Deposits Net increase in deposits Increase (Decrease) in Deposits, Total Repayments of Federal Home Loan Bank Borrowings Repayment of long-term FHLB advances Repayments of long-term FHLB advances Proceeds from (Repayments of) Short-term Debt Increase (decrease) in short-term borrowings Proceeds from (Repayments of) Short-term Debt, Total