Fair Value of Financial Instruments - Schedule of Assets and Liabilities Measured at Fair Value on a Non-recurring Basis (Detail) - USD ($)	Jun. 30, 2022	Jun. 30, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	$ 1,385,316,000	$ 1,678,696,000
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	178,000	178,000
Fair Value, Measurements, Nonrecurring [Member] | Multifamily [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	7,517,000	6,932,000
Fair Value, Measurements, Nonrecurring [Member] | Collateral Dependent Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	21,031,000	18,662,000
Fair Value, Measurements, Nonrecurring [Member] | Collateral Dependent Loans [Member] | Residential Mortgage [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	2,035,000	3,051,000
Fair Value, Measurements, Nonrecurring [Member] | Collateral Dependent Loans [Member] | Non-Residential Mortgage [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	11,479,000	8,679,000
Fair Value, Measurements, Nonrecurring [Member] | Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	178,000	178,000
Fair Value, Measurements, Nonrecurring [Member] | Other Real Estate Owned | Residential Mortgage [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	178,000	178,000
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	1,385,316,000	1,678,696,000
Significant Unobservable Inputs (Level 3) [Member] | Impaired Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	21,000,000.0	18,700,000
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Multifamily [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	7,517,000	6,932,000
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Collateral Dependent Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	21,031,000	18,662,000
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Collateral Dependent Loans [Member] | Residential Mortgage [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	2,035,000	3,051,000
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Collateral Dependent Loans [Member] | Non-Residential Mortgage [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	11,479,000	8,679,000
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	178,000	178,000
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Nonrecurring [Member] | Other Real Estate Owned | Residential Mortgage [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets	$ 178,000	$ 178,000