Loans Receivable - Performance Status of Loans Receivable (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Jun. 30, 2021
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	$ 5,024,915	$ 4,880,310
Commercial Business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	169,551	168,951
Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	121,137	93,804
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	1,527,980	1,447,721
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	2,755	3,259
Non-Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	1,085,988	1,079,444
Multi-Family Mortgage Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	2,076,003	2,039,260
Home Equity Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	41,501	47,871
One-to Four-Family Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	1,527,980	1,447,721
Nonperforming Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	5,024,915	4,880,310
Nonperforming Loans [Member] | Commercial Business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	169,551	168,951
Nonperforming Loans [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	121,137	93,804
Nonperforming Loans [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	2,755	3,259
Nonperforming Loans [Member] | Non-Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	1,085,988	1,079,444
Nonperforming Loans [Member] | Multi-Family Mortgage Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	2,076,003	2,039,260
Nonperforming Loans [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	4,944,320	4,800,543
Nonperforming Loans [Member] | Performing Financing Receivable [Member] | Commercial Business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	169,058	168,039
Nonperforming Loans [Member] | Performing Financing Receivable [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	119,346	91,576
Nonperforming Loans [Member] | Performing Financing Receivable [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	2,755	3,259
Nonperforming Loans [Member] | Performing Financing Receivable [Member] | Non-Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	1,057,798	1,042,257
Nonperforming Loans [Member] | Performing Financing Receivable [Member] | Multi-Family Mortgage Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	2,035,988	2,020,734
Nonperforming Loans [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	19,788	29,022
Nonaccrual loans with no allowance for credit losses	60,807	50,745
Total nonperforming	80,595	79,767
Nonperforming Loans [Member] | Nonperforming Financing Receivable [Member] | Commercial Business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	63	236
Nonaccrual loans with no allowance for credit losses	430	676
Total nonperforming	493	912
Nonperforming Loans [Member] | Nonperforming Financing Receivable [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans with no allowance for credit losses	1,791	2,228
Total nonperforming	1,791	2,228
Nonperforming Loans [Member] | Nonperforming Financing Receivable [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	313
Nonperforming Loans [Member] | Nonperforming Financing Receivable [Member] | Non-Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	3,667	12,612
Nonaccrual loans with no allowance for credit losses	24,523	24,575
Total nonperforming	28,190	37,187
Nonperforming Loans [Member] | Nonperforming Financing Receivable [Member] | Multi-Family Mortgage Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	11,369	8,300
Nonaccrual loans with no allowance for credit losses	28,646	10,226
Total nonperforming	40,015	18,526
Nonperforming Loans [Member] | Home Equity Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	41,501	47,871
Nonperforming Loans [Member] | Home Equity Loans [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	40,012	46,127
Nonperforming Loans [Member] | Home Equity Loans [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		452
Nonaccrual loans with no allowance for credit losses	1,176	1,292
Total nonperforming	1,489	1,744
Nonperforming Loans [Member] | One-to Four-Family Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	1,527,980	1,447,721
Nonperforming Loans [Member] | One-to Four-Family Residential Mortgage [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable, Gross	1,519,363	1,428,551
Nonperforming Loans [Member] | One-to Four-Family Residential Mortgage [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	4,376	7,422
Nonaccrual loans with no allowance for credit losses	4,241	11,748
Total nonperforming	$ 8,617	$ 19,170