Securities Available for Sale - Amortized Cost, Gross Unrealized Gains and Losses and Fair Values of Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jun. 30, 2018
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	$ 545,654
Securities available for sale, Fair value	543,891	$ 590,562
Securities available for sale, Amortized Cost	729,606	729,406
Mortgage-backed securities, Gross Unrealized Gains	2,597	3,404
Mortgage-backed securities, Gross Unrealized Losses	5,283	7,725
Investment securities available for sale, at fair value	726,920	725,085
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	545,654	589,999
Securities available for sale, Gross Unrealized Gains	1,745	3,361
Securities available for sale, Gross Unrealized Losses	3,508	2,798
Securities available for sale, Fair value	543,891	590,562
Debt Securities [Member] \| U.S. Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	3,765	4,474
Securities available for sale, Gross Unrealized Losses	28	63
Securities available for sale, Fair value	3,737	4,411
Debt Securities [Member] \| Obligations of State and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	26,634	26,793
Securities available for sale, Gross Unrealized Gains	134	4
Securities available for sale, Gross Unrealized Losses	37	709
Securities available for sale, Fair value	26,731	26,088
Debt Securities [Member] \| Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	178,830	179,959
Securities available for sale, Gross Unrealized Gains	1,583	2,795
Securities available for sale, Gross Unrealized Losses	268	134
Securities available for sale, Fair value	180,145	182,620
Debt Securities [Member] \| Collateralized Loan Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	209,530	226,881
Securities available for sale, Gross Unrealized Gains		99
Securities available for sale, Gross Unrealized Losses	1,624	914
Securities available for sale, Fair value	207,906	226,066
Debt Securities [Member] \| Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	122,928	147,925
Securities available for sale, Gross Unrealized Gains	28	463
Securities available for sale, Gross Unrealized Losses	1,359	794
Securities available for sale, Fair value	121,597	147,594
Debt Securities [Member] \| Trust Preferred Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	3,967	3,967
Securities available for sale, Gross Unrealized Losses	192	184
Securities available for sale, Fair value	3,775	3,783
Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	183,952	139,407
Mortgage-backed securities, Gross Unrealized Gains	852	43
Mortgage-backed securities, Gross Unrealized Losses	1,775	4,927
Investment securities available for sale, at fair value	183,029	134,523
Mortgage-Backed Securities [Member] \| Collateralized Mortgage Obligations Excluding Pass Through Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	22,242	25,651
Mortgage-backed securities, Gross Unrealized Losses	582	1,359
Investment securities available for sale, at fair value	21,660	24,292
Mortgage-Backed Securities [Member] \| Residential Pass-Through Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	71,663	105,810
Mortgage-backed securities, Gross Unrealized Gains	43	43
Mortgage-backed securities, Gross Unrealized Losses	1,193	3,494
Investment securities available for sale, at fair value	70,513	102,359
Mortgage-Backed Securities [Member] \| Commercial Pass-Through Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized Cost	90,047	7,946
Mortgage-backed securities, Gross Unrealized Gains	809
Mortgage-backed securities, Gross Unrealized Losses		74
Investment securities available for sale, at fair value	$ 90,856	$ 7,872

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
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