Loans and Allowance for Loan Losses - Age Analysis of Recorded Investment in Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Total	$ 6,638,105
Total loans	6,638,105	$ 6,704,674
Financing Receivables, 30 to 59 Days Past Due [Member]
Total	11,978	36,947
Financing Receivables, 60 to 89 Days Past Due [Member]
Total	4,457	11,519
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	14,433	18,915
Total Past Due [Member]
Total	30,869	67,381
Current [Member]
Total	6,607,236	6,637,293
Multi-family Residential Portfolio Segment [Member]
Total	2,519,227
Total loans	2,519,227	2,535,977
Multi-family Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Total	3,652	7,582
Multi-family Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Total	4,193	3,186
Multi-family Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	2,652	2,777
Multi-family Residential Portfolio Segment [Member] | Total Past Due [Member]
Total	10,497	13,545
Multi-family Residential Portfolio Segment [Member] | Current [Member]
Total	2,508,730	2,522,432
Commercial Real Estate
Total	1,777,375
Total loans	1,777,375	1,758,384
Commercial Real Estate | Financing Receivables, 30 to 59 Days Past Due [Member]
Total	5,743	17,903
Commercial Real Estate | Financing Receivables, 60 to 89 Days Past Due [Member]
Total	0	5,123
Commercial Real Estate | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	640	4,313
Commercial Real Estate | Total Past Due [Member]
Total	6,383	27,339
Commercial Real Estate | Current [Member]
Total	1,770,992	1,731,045
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
Total	574,936
Total loans	574,936	606,885
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Total	2,319	5,673
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Total	0	1,132
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	1,321	1,433
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Total Past Due [Member]
Total	3,640	8,238
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Current [Member]
Total	571,296	598,647
One-To-Four Family - Residential Portfolio Segment [Member]
Total	277,812
Total loans	269,496	244,640
One-To-Four Family - Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Total	163	3,087
One-To-Four Family - Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Total	224	805
One-To-Four Family - Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	7,482	5,313
One-To-Four Family - Residential Portfolio Segment [Member] | Total Past Due [Member]
Total	7,870	9,205
One-To-Four Family - Residential Portfolio Segment [Member] | Current [Member]
Total	261,626	235,435
Co-Operative Apartments Portfolio Segment [Member]
Total loans	8,316	8,051
Co-Operative Apartments Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Total	0	0
Co-Operative Apartments Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Total	0	0
Co-Operative Apartments Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	0	0
Co-Operative Apartments Portfolio Segment [Member] | Total Past Due [Member]
Total	0	0
Co-Operative Apartments Portfolio Segment [Member] | Current [Member]
Total	8,316	8,051
Construction Portfolio Segment [Member]
Total	59,473
Total loans	59,473	83,161
Construction Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Total	0	750
Construction Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Total	0	0
Construction Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	0	0
Construction Portfolio Segment [Member] | Total Past Due [Member]
Total	0	750
Construction Portfolio Segment [Member] | Current [Member]
Total	59,473	82,411
Small Business Administration Portfolio Segment [Member]
Total	91,836
Total loans	91,836	165,570
Small Business Administration Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Total	0	1,823
Small Business Administration Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Total	0	0
Small Business Administration Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	952	1,168
Small Business Administration Portfolio Segment [Member] | Total Past Due [Member]
Total	952	2,991
Small Business Administration Portfolio Segment [Member] | Current [Member]
Total	90,884	162,579
Taxi Medallion Portfolio Segment [Member]
Total loans		2,597
Taxi Medallion Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Total		0
Taxi Medallion Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Total		0
Taxi Medallion Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total		2,318
Taxi Medallion Portfolio Segment [Member] | Total Past Due [Member]
Total		2,318
Taxi Medallion Portfolio Segment [Member] | Current [Member]
Total		279
Commercial Business and Other Portfolio Segment [Member]
Total loans	1,337,446	1,299,409
Commercial Business and Other Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Total	101	129
Commercial Business and Other Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Total	40	1,273
Commercial Business and Other Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Total	1,386	1,593
Commercial Business and Other Portfolio Segment [Member] | Total Past Due [Member]
Total	1,527	2,995
Commercial Business and Other Portfolio Segment [Member] | Current [Member]
Total	$ 1,335,919	$ 1,296,414