Fair Value of Financial Instruments - Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Jun. 30, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities available for sale	$ 666,602	$ 725,085
Investment securities held to maturity, amortized cost	598,318	589,730
Investment securities held to maturity	592,151	579,499
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities available for sale	665,602	724,085
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities available for sale	1,000	1,000
Carrying Amount [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	51,483	128,864
Investment securities available for sale	666,602	725,085
Investment securities held to maturity, amortized cost	598,318	589,730
Loans held-for-sale	1,001	863
Net loans receivable	4,719,866	4,470,483
FHLB Stock	64,514	59,004
Interest receivable	19,435	18,510
Interest rate swaps	22,109	31,881
Deposits	4,173,434	4,073,604
Borrowings	1,310,547	1,198,646
Interest payable on deposits	1,446	675
Interest payable on borrowings	3,866	2,427
Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	51,483	128,864
Investment securities available for sale	666,602	725,085
Investment securities held to maturity	592,151	579,499
Loans held-for-sale	1,001	863
Net loans receivable	4,588,099	4,367,150
Interest receivable	19,435	18,510
Interest rate swaps	22,109	31,881
Deposits	4,160,515	4,055,543
Borrowings	1,314,802	1,199,601
Interest payable on deposits	1,446	675
Interest payable on borrowings	3,866	2,427
Fair Value [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	51,483	128,864
Interest receivable	6	32
Deposits	2,287,548	2,056,966
Fair Value [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities available for sale	665,602	724,085
Investment securities held to maturity	592,151	579,499
Loans held-for-sale	1,001	863
Interest receivable	5,060	5,252
Interest rate swaps	22,109	31,881
Interest payable on deposits	1,446	675
Fair Value [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities available for sale	1,000	1,000
Net loans receivable	4,588,099	4,367,150
Interest receivable	14,369	13,226
Deposits	1,872,967	1,998,577
Borrowings	1,314,802	1,199,601
Interest payable on borrowings	$ 3,866	$ 2,427

Interest payable fair value disclosure.

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Interest receivable fair value disclosure.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Carrying amount as of the balance sheet date of the assets arising from derivative contracts and hedging activities, which are expected to be converted into cash or otherwise disposed of after a year or beyond the normal operating cycle, if longer.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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