Loans Held for Sale - Delinquent and Non-performing Loans Sold During the Period Indicated (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) loan	Dec. 31, 2019 USD ($) loan	Dec. 31, 2018 USD ($) loan
Nonperforming Financial Instruments [Member]
Loans sold | loan	2	11	12
Proceeds	$ 580	$ 13,048	$ 8,739
Net (charge-offs) recoveries	0	(1)	68
Net gain (loss)	$ 42	$ 756	$ (225)
Nonperforming Financial Instruments [Member] | Multi-family Residential Portfolio Segment [Member]
Loans sold | loan	1	5	4
Proceeds	$ 284	$ 2,115	$ 1,559
Net (charge-offs) recoveries	0	0	0
Net gain (loss)	$ 42	$ 367	$ 0
Nonperforming Financial Instruments [Member] | Commercial Real Estate
Loans sold | loan		2	4
Proceeds		$ 6,800	$ 6,065
Net (charge-offs) recoveries		0	0
Net gain (loss)		$ 383	$ (235)
Nonperforming Financial Instruments [Member] | Commercial Business and Other Portfolio Segment [Member]
Loans sold | loan		1
Proceeds		$ 3,248
Net (charge-offs) recoveries		0
Net gain (loss)		$ 0
Nonperforming Financial Instruments [Member] | One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Loans sold | loan	1	3	2
Proceeds	$ 296	$ 885	$ 725
Net (charge-offs) recoveries	0	(1)	(4)
Net gain (loss)	$ 0	$ 6	$ 0
Nonperforming Financial Instruments [Member] | One-To-Four Family - Residential Portfolio Segment [Member]
Loans sold | loan			2
Proceeds			$ 390
Net (charge-offs) recoveries			72
Net gain (loss)			$ 10
Performing Financial Instruments [Member]
Loans sold | loan	2	3	9
Proceeds	$ 6,913	$ 2,069	$ 5,671
Net (charge-offs) recoveries	0	0	0
Net gain (loss)	$ 6	$ 114	$ 393
Performing Financial Instruments [Member] | Commercial Business and Other Portfolio Segment [Member]
Loans sold | loan	1
Proceeds	$ 6,139
Net (charge-offs) recoveries	0
Net gain (loss)	$ (62)
Performing Financial Instruments [Member] | Small Business Administration Portfolio Segment [Member]
Loans sold | loan	1	3	9
Proceeds	$ 774	$ 2,069	$ 5,671
Net (charge-offs) recoveries	0	0	0
Net gain (loss)	$ 68	$ 114	$ 393