Nature of Business and Summary of Significant Accounting Policies - Additional Information (Details)			3 Months Ended		6 Months Ended		12 Months Ended
	May 06, 2029 USD ($)	Jul. 10, 2020 BranchOffice MortgageOffice	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) Segment BranchLease	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Number of branch banking offices		18
Business Acquisition, Effective Date of Acquisition		Jul. 10, 2020			Jul. 10, 2020
Business Acquisition, Name of Acquired Entity		Mortgage World			Mortgage World
Provision for loan losses (Note 5) | $	$ 1,417,000		$ 586,000	$ 271,000	$ 1,272,000	$ 1,417,000	$ 2,443,000
Minimum collection percentage of securities required to be considered as a maturity					85.00%
Period of historical loss experience to estimate allowance for loan losses					36 months
Percentage of largest amount of tax benefits likely to realize					50.00%
Percentage of employee discretionary matching, profit sharing and safe harbor contributions, maximum					4.00%
Number of business segment | Segment					2
Number of leased branches | BranchLease					13
Construction Loans
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Provision for loan losses (Note 5) | $			29,000	(235,000)	$ 136,000	(112,000)	38,000
Commercial Real Estate Portfolio Segment
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Period on which interest rate is adjusted					5 years
Commercial Portfolio Segment
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Provision for loan losses (Note 5) | $			$ 98,000	$ (41,000)	$ 88,000	$ (63,000)	$ (95,000)
Minimum
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Percentage of loan to value ratio					65.00%
Minimum | Construction Loans
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Loan term					6 months
Minimum | Commercial Real Estate Portfolio Segment
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Loan amortization period					15 years
Balloon payments period of loan					10 years
Minimum | Commercial Portfolio Segment
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Loan term					5 years
Maximum
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Percentage of loan to value ratio					90.00%
Maximum | Construction Loans
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Loan term					2 years
Maximum | Commercial Real Estate Portfolio Segment
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Percentage of loan to value ratio					75.00%
Loan amortization period					30 years
Balloon payments period of loan					15 years
Maximum | Commercial Portfolio Segment
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Loan term					7 years
COVID-19
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Provision for loan losses (Note 5) | $					$ 1,300
Bronx
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Number of branch banking offices		4
Manhattan
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Number of branch banking offices		2
Queens
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Number of branch banking offices		3
Number of branch mortgage offices | MortgageOffice		2
Brooklyn
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Number of branch banking offices		3
Union City
Nature Of Business And Summary Of Significant Accounting Policies Table Of Statement [Line Items]
Number of branch banking offices		1