Fair Value of Financial Instruments - Summary of Carrying Amounts and Estimated Fair Values of Bank's Financial Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Jun. 30, 2021
Financial assets:
Held to maturity debt securities	$ 379,500	$ 342,137
Available for sale debt securities	37,185	57,387
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	158,892	159,305
Held to maturity debt securities	410,896	337,584
Available for sale debt securities	37,185	57,387
Loans receivable, net	1,285,886	1,229,451
Accrued interest receivable	6,583	6,398
FHLB stock	3,715	4,507
Financial liabilities:
Mortgage escrow funds	8,744	10,536
Advances from FHLB	48,357	65,957
Accrued interest payable	117	146
Carrying Amount [Member] | Derivatives - Interest Rate Contracts [Member]
Financial assets:
Derivative assets - interest rate contracts	4,843	4,232
Financial liabilities:
Derivative liabilities - interest rate contracts	4,843	4,232
Carrying Amount [Member] | Demand, NOW, Money Market Deposits and Savings Accounts [Member]
Financial liabilities:
Deposits	1,279,627	1,116,667
Carrying Amount [Member] | Time Deposits [Member]
Financial liabilities:
Deposits	345,092	375,015
Total [Member]
Financial assets:
Cash and cash equivalents	158,892	159,305
Held to maturity debt securities	379,500	342,137
Available for sale debt securities	37,185	57,387
Loans receivable, net	1,254,851	1,234,116
Accrued interest receivable	6,583	6,398
Financial liabilities:
Mortgage escrow funds	8,744	10,536
Advances from FHLB	48,950	67,334
Accrued interest payable	117	146
Total [Member] | Derivatives - Interest Rate Contracts [Member]
Financial assets:
Derivative assets - interest rate contracts	4,843	4,232
Financial liabilities:
Derivative liabilities - interest rate contracts	4,843	4,232
Total [Member] | Demand, NOW, Money Market Deposits and Savings Accounts [Member]
Financial liabilities:
Deposits	1,279,627	1,116,667
Total [Member] | Time Deposits [Member]
Financial liabilities:
Deposits	348,306	380,948
Level 1 [Member]
Financial assets:
Cash and cash equivalents	158,892	159,305
Financial liabilities:
Mortgage escrow funds	8,744	10,536
Accrued interest payable	1	1
Level 1 [Member] | Demand, NOW, Money Market Deposits and Savings Accounts [Member]
Financial liabilities:
Deposits	1,279,627	1,116,667
Level 2 [Member]
Financial assets:
Held to maturity debt securities	324,079	305,671
Available for sale debt securities	32,207	54,256
Accrued interest receivable	1,926	1,341
Financial liabilities:
Advances from FHLB	48,950	67,334
Accrued interest payable	116	145
Level 2 [Member] | Derivatives - Interest Rate Contracts [Member]
Financial assets:
Derivative assets - interest rate contracts	4,843	4,232
Financial liabilities:
Derivative liabilities - interest rate contracts	4,843	4,232
Level 2 [Member] | Time Deposits [Member]
Financial liabilities:
Deposits	348,306	380,948
Level 3 [Member]
Financial assets:
Held to maturity debt securities	55,421	36,466
Available for sale debt securities	4,978	3,131
Loans receivable, net	1,254,851	1,234,116
Accrued interest receivable	$ 4,657	$ 5,057