Loan Quality and Allowance for Loan Losses - Allowance for Loan Losses and Balance of Loans Receivable (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Jun. 30, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance	$ 33,526	$ 30,066	$ 30,865	$ 29,286
Allowance, Loans individually evaluated for impairment	318		318		$ 306
Allowance, Loans collectively evaluated for impairment	32,787		32,787		30,559
Allowance	33,105	30,248	33,105	30,248
Loans individually evaluated for impairment	25,633		25,633		22,913
Loans collectively evaluated for impairment	4,689,543		4,689,543		4,544,634
Loans and Leases Receivable, Gross	4,715,516		4,715,516		4,567,915
Loans receivable, unamortized yield adjustments	(55,712)		(55,712)		(66,567)
Loans receivable	4,659,804		4,659,804		4,501,348
Total charge offs	(260)	(325)	(721)	(1,339)
Total recoveries	18	84	69	312
Total provision (reversal) for Loan Losses	(179)	423	2,892	1,989
Residential Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance	2,977	2,440	2,479	2,384
Allowance, Loans individually evaluated for impairment	36		36		79
Allowance, Loans collectively evaluated for impairment	3,079		3,079		2,400
Allowance	3,115	2,454	3,115	2,454
Loans individually evaluated for impairment	13,446		13,446		11,931
Loans collectively evaluated for impairment	1,311,569		1,311,569		1,285,423
Loans and Leases Receivable, Gross	1,325,105		1,325,105		1,297,453
Total charge offs		(61)	(83)	(471)
Total recoveries			0	77
Total provision (reversal) for Loan Losses	138	75	719	464
Non-Residential Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance	9,918	9,665	9,787	9,939
Allowance, Loans collectively evaluated for impairment	9,575		9,575		9,787
Allowance	9,575	9,885	9,575	9,885
Loans individually evaluated for impairment	8,956		8,956		5,344
Loans collectively evaluated for impairment	1,240,259		1,240,259		1,297,617
Loans and Leases Receivable, Gross	1,249,215		1,249,215		1,302,961
Total charge offs		(7)	(54)	(45)
Total recoveries			2
Total provision (reversal) for Loan Losses	(343)	227	(160)	(9)
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance	305	246	258	35
Allowance, Loans collectively evaluated for impairment	149		149		258
Allowance	149	253	149	253
Loans collectively evaluated for impairment	14,377		14,377		23,271
Loans and Leases Receivable, Gross	14,377		14,377		23,271
Total charge offs			0
Total recoveries			0
Total provision (reversal) for Loan Losses	(156)	7	(109)	218
Commercial Business [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance	2,514	2,706	2,552	1,709
Allowance, Loans individually evaluated for impairment	282		282		227
Allowance, Loans collectively evaluated for impairment	2,282		2,282		2,325
Allowance	2,564	2,686	2,564	2,686
Loans individually evaluated for impairment	1,625		1,625		3,921
Loans collectively evaluated for impairment	64,601		64,601		81,635
Loans and Leases Receivable, Gross	66,476		66,476		85,825
Total charge offs	(184)	(89)	(369)	(95)
Total recoveries		55	0	89
Total provision (reversal) for Loan Losses	234	14	381	983
Other Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance	253	643	413	777
Allowance, Loans collectively evaluated for impairment	201		201		413
Allowance	201	527	201	527
Loans collectively evaluated for impairment	5,984		5,984		9,060
Loans and Leases Receivable, Gross	5,984		5,984		9,060
Total charge offs	(76)	(167)	(215)	(727)
Total recoveries	18	29	67	81
Total provision (reversal) for Loan Losses	6	22	(64)	396
Multi-Family Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance	17,095	13,909	14,946	13,941
Allowance, Loans collectively evaluated for impairment	17,012		17,012		14,946
Allowance	17,012	14,010	17,012	14,010
Loans individually evaluated for impairment	81		81		116
Loans collectively evaluated for impairment	1,956,490		1,956,490		1,758,468
Loans and Leases Receivable, Gross	1,956,571		1,956,571		1,758,584
Total charge offs			0
Total recoveries			0
Total provision (reversal) for Loan Losses	(83)	101	2,066	69
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans acquired with deteriorated credit quality	340		340		368
Receivables Acquired with Deteriorated Credit Quality [Member] \| Residential Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans acquired with deteriorated credit quality	90		90		99
Receivables Acquired with Deteriorated Credit Quality [Member] \| Commercial Business [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans acquired with deteriorated credit quality	250		250		269
Home Equity Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance	464	457	430	501
Allowance, Loans collectively evaluated for impairment	489		489		430
Allowance	489	433	489	433
Loans individually evaluated for impairment	1,525		1,525		1,601
Loans collectively evaluated for impairment	96,263		96,263		89,160
Loans and Leases Receivable, Gross	97,788		97,788		$ 90,761
Total charge offs		(1)	0	(1)
Total recoveries			0	65
Total provision (reversal) for Loan Losses	$ 25	$ (23)	$ 59	$ (132)

Provision (reversal) for loan and lease losses.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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Amount of direct write-downs of financing receivables charged against the allowance.

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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