Loans and Allowance for Loan Losses - Troubled Debt Restructurings That Are Performing (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($) loan	Jun. 30, 2019 loan	Jun. 30, 2020 USD ($) contract loan	Jun. 30, 2019 loan	Dec. 31, 2019 USD ($) contract
Number | loan	0	0	0	0
Performing Financial Instruments [Member]
Number | contract			22		24
Recorded investment | $	$ 5,983		$ 5,983		$ 6,494
Multi-Family Residential [Member] | Performing Financial Instruments [Member]
Number | contract			7		7
Recorded investment | $	1,860		$ 1,860		$ 1,873
One-To-Four Family - Mixed Used Property [Member] | Performing Financial Instruments [Member]
Number | contract			3		4
Recorded investment | $	1,143		$ 1,143		$ 1,481
One-To-Four Family - Residential [Member] | Performing Financial Instruments [Member]
Number | contract			3		3
Recorded investment | $	518		$ 518		$ 531
Taxi Medallion Portfolio Segment [Member] | Performing Financial Instruments [Member]
Number | contract			6		7
Recorded investment | $	1,512		$ 1,512		$ 1,668
Commercial Business and Other [Member] | Performing Financial Instruments [Member]
Number | contract			3		3
Recorded investment | $	$ 950		$ 950		$ 941