Loans - Risk Category of Mortgage and Non-mortgage Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
2023	$ 122,672
2022	1,232,209
2021	774,177
2020	585,318
2019	789,811
Prior	3,056,055
Revolving Loans Amortized Cost Basis	330,436
Revolving Loans converted to term loans	13,498
Total	6,904,176
Gross charge-offs
Prior	31
Revolving Loans Amortized Cost Basis	9,267
Total	9,298	$ 1,036
Pass [Member]
2023	122,672
2022	1,223,186
2021	759,071
2020	577,335
2019	720,738
Prior	2,881,408
Revolving Loans Amortized Cost Basis	321,383
Revolving Loans converted to term loans	11,827
Total	6,617,620
Watch [Member]
2022	3,797
2021	10,983
2020	3,224
2019	53,795
Prior	152,679
Revolving Loans Amortized Cost Basis	1,272
Revolving Loans converted to term loans	1,228
Total	226,978
Special Mention [Member]
2021	1,679
2020	4,759
2019	15,231
Prior	6,329
Total	27,998
Substandard [Member]
2022	5,226
2021	2,444
2019	47
Prior	15,639
Revolving Loans Amortized Cost Basis	3,079
Revolving Loans converted to term loans	443
Total	26,878
Doubtful [Member]
Revolving Loans Amortized Cost Basis	4,702
Total	4,702
One-To-Four Family - Residential Portfolio Segment [Member]
2023	4,146
2022	24,088
2021	8,922
2020	18,034
2019	42,303
Prior	120,626
Revolving Loans Amortized Cost Basis	7,968
Revolving Loans converted to term loans	13,498
Total	239,585
Gross charge-offs
Prior	6
Total	6
One-To-Four Family - Residential Portfolio Segment [Member] | Pass [Member]
2023	4,146
2022	23,573
2021	8,640
2020	18,034
2019	41,567
Prior	114,894
Revolving Loans Amortized Cost Basis	7,905
Revolving Loans converted to term loans	11,827
Total	230,586
One-To-Four Family - Residential Portfolio Segment [Member] | Watch [Member]
2022	515
2021	282
2019	736
Prior	1,374
Revolving Loans Amortized Cost Basis	63
Revolving Loans converted to term loans	1,228
Total	4,198
One-To-Four Family - Residential Portfolio Segment [Member] | Substandard [Member]
Prior	4,358
Revolving Loans converted to term loans	443
Total	4,801
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member]
2023	5,519
2022	44,641
2021	42,764
2020	33,238
2019	63,806
Prior	362,003
Total	551,971
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Pass [Member]
2023	5,519
2022	44,641
2021	42,764
2020	32,360
2019	63,079
Prior	353,651
Total	542,014
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Watch [Member]
2020	878
2019	727
Prior	6,541
Total	8,146
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Special Mention [Member]
Prior	840
Total	840
One-To-Four Family - Mixed-Use Property Portfolio Segment [Member] | Substandard [Member]
Prior	971
Total	971
Commercial Real Estate [Member]
2023	18,305
2022	329,094
2021	182,527
2020	151,568
2019	232,948
Prior	991,265
Total	1,905,707
Commercial Real Estate [Member] | Pass [Member]
2023	18,305
2022	327,129
2021	181,002
2020	151,568
2019	223,378
Prior	969,174
Total	1,870,556
Commercial Real Estate [Member] | Watch [Member]
2022	1,965
2021	1,525
2019	9,570
Prior	21,899
Total	34,959
Commercial Real Estate [Member] | Special Mention [Member]
Prior	183
Total	183
Commercial Real Estate [Member] | Substandard [Member]
Prior	9
Total	9
Construction Portfolio Segment
2023	3,089
2022	1,899
2021	17,660
Prior	2,600
Revolving Loans Amortized Cost Basis	35,125
Total	60,373
Construction Portfolio Segment | Pass [Member]
2023	3,089
2022	1,899
2021	17,660
Revolving Loans Amortized Cost Basis	35,125
Total	57,773
Construction Portfolio Segment | Substandard [Member]
Prior	2,600
Total	2,600
Multi-family Residential Portfolio Segment [Member]
2023	48,865
2022	481,080
2021	285,357
2020	225,094
2019	310,618
Prior	1,248,559
Revolving Loans Amortized Cost Basis	4,601
Total	2,604,174
Multi-family Residential Portfolio Segment [Member] | Pass [Member]
2023	48,865
2022	480,178
2021	285,357
2020	222,748
2019	310,618
Prior	1,215,855
Revolving Loans Amortized Cost Basis	4,601
Total	2,568,222
Multi-family Residential Portfolio Segment [Member] | Watch [Member]
2022	902
2020	2,346
Prior	26,616
Total	29,864
Multi-family Residential Portfolio Segment [Member] | Special Mention [Member]
Prior	1,326
Total	1,326
Multi-family Residential Portfolio Segment [Member] | Substandard [Member]
Prior	4,762
Total	4,762
Commercial Business Secured By Portfolio Segment [member]
2023	13,955
2022	184,487
2021	138,718
2020	108,771
2019	83,245
Prior	212,560
Total	741,736
Commercial Business Secured By Portfolio Segment [member] | Pass [Member]
2023	13,955
2022	181,634
2021	138,718
2020	108,771
2019	41,827
Prior	153,310
Total	638,215
Commercial Business Secured By Portfolio Segment [member] | Watch [Member]
2019	26,220
Prior	59,250
Total	85,470
Commercial Business Secured By Portfolio Segment [member] | Special Mention [Member]
2019	15,198
Total	15,198
Commercial Business Secured By Portfolio Segment [member] | Substandard [Member]
2022	2,853
Total	2,853
Commercial Business Portfolio Segment [Member]
2023	28,793
2022	163,585
2021	92,609
2020	44,636
2019	56,175
Prior	109,280
Revolving Loans Amortized Cost Basis	282,672
Total	777,750
Gross charge-offs
Revolving Loans Amortized Cost Basis	9,267
Total	9,267
Commercial Business Portfolio Segment [Member] | Pass [Member]
2023	28,793
2022	160,797
2021	81,582
2020	39,877
2019	39,603
Prior	71,738
Revolving Loans Amortized Cost Basis	273,682
Total	696,072
Commercial Business Portfolio Segment [Member] | Watch [Member]
2022	415
2021	8,583
2019	16,492
Prior	31,837
Revolving Loans Amortized Cost Basis	1,209
Total	58,536
Commercial Business Portfolio Segment [Member] | Special Mention [Member]
2020	4,759
2019	33
Prior	3,943
Total	8,735
Commercial Business Portfolio Segment [Member] | Substandard [Member]
2022	2,373
2021	2,444
2019	47
Prior	1,762
Revolving Loans Amortized Cost Basis	3,079
Total	9,705
Commercial Business Portfolio Segment [Member] | Doubtful [Member]
Revolving Loans Amortized Cost Basis	4,702
Total	4,702
Small Business Administration Portfolio Segment [Member]
2022	3,335
2021	5,620
2020	3,977
2019	716
Prior	9,112
Total	22,760
Gross charge-offs
Prior	6
Total	6	$ 1,028
Small Business Administration Portfolio Segment [Member] | Pass [Member]
2022	3,335
2021	3,348
2020	3,977
2019	666
Prior	2,736
Total	14,062
Small Business Administration Portfolio Segment [Member] | Watch [Member]
2021	593
2019	50
Prior	5,162
Total	5,805
Small Business Administration Portfolio Segment [Member] | Special Mention [Member]
2021	1,679
Prior	37
Total	1,716
Small Business Administration Portfolio Segment [Member] | Substandard [Member]
Prior	1,177
Total	1,177
Other Portfolio Segment [Member]
Prior	50
Revolving Loans Amortized Cost Basis	70
Total	120
Gross charge-offs
Prior	19
Total	19
Other Portfolio Segment [Member] | Pass [Member]
Prior	50
Revolving Loans Amortized Cost Basis	70
Total	120
Consumer Portfolio Segment [Member]
Mortgage Loans in Process of Foreclosure, Amount	$ 5,200		$ 5,200