Fair Value of Financial Instruments - Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment securities available for sale	$ 1,231,691	$ 714,263
Investment securities held to maturity, amortized cost	37,888	576,652
Investment securities held to maturity	38,683	584,678
Interest rate swaps, liabilities	369	140
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	1,230,691	713,263
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	129,305	38,935
Investment securities available for sale	1,231,691	714,263
Investment securities held to maturity, amortized cost	37,888	576,652
Loans held-for-sale	10,495	12,267
Net loans receivable	4,572,306	4,645,654
FHLB Stock	63,739	64,190
Interest receivable	19,393	19,360
Interest rate swaps and caps	2,430	3,856
Deposits	4,197,250	4,147,610
Borrowings	1,281,118	1,321,982
Interest payable on deposits	2,720	3,106
Interest payable on borrowings	3,621	3,899
Interest rate swaps, liabilities	369	140
Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	129,305	38,935
Investment securities available for sale	1,231,691	714,263
Investment securities held to maturity	38,683	584,678
Loans held-for-sale	10,700	12,501
Net loans receivable	4,533,681	4,630,853
Interest receivable	19,393	19,360
Interest rate swaps and caps	2,430	3,856
Deposits	4,205,384	4,152,558
Borrowings	1,296,639	1,337,560
Interest payable on deposits	2,720	3,106
Interest payable on borrowings	3,621	3,899
Interest rate swaps, liabilities	369	140
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	129,305	38,935
Interest receivable	23	11
Deposits	2,054,548	1,943,154
Interest payable on deposits	366	367
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	1,230,691	713,263
Investment securities held to maturity	38,683	584,678
Loans held-for-sale	10,700	12,501
Interest receivable	5,357	5,278
Interest rate swaps and caps	2,430	3,856
Interest rate swaps, liabilities	369	140
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	4,533,681	4,630,853
Interest receivable	14,013	14,071
Deposits	2,150,836	2,209,404
Borrowings	1,296,639	1,337,560
Interest payable on deposits	2,354	2,739
Interest payable on borrowings	$ 3,621	$ 3,899

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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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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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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