LOANS HELD FOR INVESTMENT, NET - Credit Quality Indicators (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Credit Risk Profile of Real Estate Loans [Abstract]
Total loans, net of fair value hedge basis point adjustments	$ 10,773,428	$ 10,566,831
Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	922,902
2022/2021	2,700,103	2,845,426
2021/2020	1,582,274	1,733,872
2020/2019	954,855	1,196,053
2019/2018	960,030	1,024,753
2018/2017 and Prior	2,257,567	522,005
2016 and Prior		2,175,148
Revolving	704,128	726,711
Revolving-Term	60,048	59,850
Total loans, net of fair value hedge basis point adjustments	10,141,907	10,283,818
Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	481
2022/2021	53,182	6,634
2021/2020	45,366
2020/2019	92,825	20,549
2019/2018	27,827	17,365
2018/2017 and Prior	70,219	16,628
2016 and Prior		31,664
Revolving	21,267	9,641
Revolving-Term	26,082	1,204
Total loans, net of fair value hedge basis point adjustments	337,249	103,685
Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	1,857	5,242
2021/2020	2,196	2,052
2020/2019	96,805	23,234
2019/2018	14,483	19,143
2018/2017 and Prior	130,103	22,819
2016 and Prior		66,232
Revolving	15,567	11,290
Revolving-Term	20,167	10,505
Total loans, net of fair value hedge basis point adjustments	281,178	160,517
Doubtful
Credit Risk Profile of Real Estate Loans [Abstract]
2019/2018		8,332
2018/2017 and Prior	748	752
2016 and Prior		2,048
Total loans, net of fair value hedge basis point adjustments	748	11,132
Total real estate loans
Credit Risk Profile of Real Estate Loans [Abstract]
Total loans, net of fair value hedge basis point adjustments	9,694,144	9,487,440
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs 2022/2021		477
YTD Gross Charge-Offs 2021/2020		4,720
YTD Gross Charge-Offs 2020/2019		2,088
YTD Gross Charge-Offs 2018 and Prior/2017 and Prior		2,414
YTD Gross Charge-Offs Revolving		1,460
YTD Gross Charge-Offs Revolving-Term		242
YTD Gross Charge-Offs	16	11,401	$ 3,817
Excludes Other Loans
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021		2,857,302
2021/2020		1,735,924
2020/2019		1,239,836
2019/2018		1,069,593
2018/2017 and Prior		562,204
2016 and Prior		2,275,092
Revolving		747,642
Revolving-Term		71,559
Total loans, net of fair value hedge basis point adjustments		10,559,152
C&I
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	61,252
2022/2021	152,914	184,359
2021/2020	28,109	37,755
2020/2019	31,853	48,361
2019/2018	28,114	49,859
2018/2017 and Prior	49,862	23,871
2016 and Prior		46,466
Revolving	657,474	648,912
Revolving-Term	57,360	32,129
Total loans, net of fair value hedge basis point adjustments	1,066,938	1,071,712
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs 2022/2021		477
YTD Gross Charge-Offs 2021/2020	77	4,720
YTD Gross Charge-Offs 2020/2019	38	2,088
YTD Gross Charge-Offs 2019/2018	4,166
YTD Gross Charge-Offs 2018 and Prior/2017 and Prior	2,229	2,414
YTD Gross Charge-Offs Revolving	5,464	1,460
YTD Gross Charge-Offs Revolving-Term	3,390	242
YTD Gross Charge-Offs	15,364	11,401	4,984
C&I | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	60,771
2022/2021	138,145	175,347
2021/2020	24,865	36,511
2020/2019	25,371	42,103
2019/2018	25,142	37,030
2018/2017 and Prior	37,019	20,628
2016 and Prior		33,343
Revolving	620,799	628,560
Revolving-Term	31,467	22,239
Total loans, net of fair value hedge basis point adjustments	963,579	995,761
C&I | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	481
2022/2021	12,912	3,770
2021/2020	1,199
2020/2019	905	894
2019/2018	1,204	1,529
2018/2017 and Prior	159	1,521
2016 and Prior		843
Revolving	21,108	9,062
Revolving-Term	7,444	478
Total loans, net of fair value hedge basis point adjustments	45,412	18,097
C&I | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	1,857	5,242
2021/2020	2,045	1,244
2020/2019	5,577	5,364
2019/2018	1,768	2,968
2018/2017 and Prior	11,936	970
2016 and Prior		10,232
Revolving	15,567	11,290
Revolving-Term	18,449	9,412
Total loans, net of fair value hedge basis point adjustments	57,199	46,722
C&I | Doubtful
Credit Risk Profile of Real Estate Loans [Abstract]
2019/2018		8,332
2018/2017 and Prior	748	752
2016 and Prior		2,048
Total loans, net of fair value hedge basis point adjustments	748	11,132
One-to-four family residential and cooperative/condominium apartment
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	170,601
2022/2021	213,479	225,031
2021/2020	102,684	108,185
2020/2019	70,529	73,758
2019/2018	62,693	66,742
2018/2017 and Prior	221,875	67,180
2016 and Prior		176,292
Revolving	31,364	41,751
Revolving-Term	14,330	14,382
Total loans, net of fair value hedge basis point adjustments	887,555	773,321
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving-Term	14
YTD Gross Charge-Offs	14		20
One-to-four family residential and cooperative/condominium apartment | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	170,601
2022/2021	213,479	225,031
2021/2020	102,684	108,185
2020/2019	69,524	72,732
2019/2018	62,356	65,515
2018/2017 and Prior	213,131	66,038
2016 and Prior		164,338
Revolving	31,205	41,172
Revolving-Term	12,493	12,563
Total loans, net of fair value hedge basis point adjustments	875,473	755,574
One-to-four family residential and cooperative/condominium apartment | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2018/2017 and Prior	33	735
2016 and Prior		1,175
Revolving	159	579
Revolving-Term	776	726
Total loans, net of fair value hedge basis point adjustments	968	3,215
One-to-four family residential and cooperative/condominium apartment | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2020/2019	1,005	1,026
2019/2018	337	1,227
2018/2017 and Prior	8,711	407
2016 and Prior		10,779
Revolving-Term	1,061	1,093
Total loans, net of fair value hedge basis point adjustments	11,114	14,532
Multifamily residential and residential mixed-use
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	256,822
2022/2021	1,340,197	1,386,549
2021/2020	587,686	582,393
2020/2019	316,312	328,718
2019/2018	393,912	414,117
2018/2017 and Prior	1,113,081	147,385
2016 and Prior		1,155,080
Revolving	4,841	12,584
Revolving-Term	4,325
Total loans, net of fair value hedge basis point adjustments	4,017,176	4,026,826
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs 2018 and Prior/2017 and Prior	2
YTD Gross Charge-Offs	2		391
Multifamily residential and residential mixed-use | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	256,822
2022/2021	1,340,197	1,386,549
2021/2020	578,352	582,393
2020/2019	283,633	316,424
2019/2018	384,937	395,933
2018/2017 and Prior	981,820	127,074
2016 and Prior		1,107,281
Revolving	4,841	12,584
Revolving-Term	4,325
Total loans, net of fair value hedge basis point adjustments	3,834,927	3,928,238
Multifamily residential and residential mixed-use | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2021/2020	9,334
2020/2019	3,880
2019/2018	3,886	11,183
2018/2017 and Prior	64,273
2016 and Prior		14,168
Total loans, net of fair value hedge basis point adjustments	81,373	25,351
Multifamily residential and residential mixed-use | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2020/2019	28,799	12,294
2019/2018	5,089	7,001
2018/2017 and Prior	66,988	20,311
2016 and Prior		33,631
Total loans, net of fair value hedge basis point adjustments	100,876	73,237
Commercial real estate ("CRE")
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	417,973
2022/2021	1,019,518	1,024,486
2021/2020	837,194	854,391
2020/2019	715,891	777,757
2019/2018	502,703	522,932
2018/2017 and Prior	1,073,382	323,768
2016 and Prior		895,167
Revolving	24,839	34,362
Revolving-Term	29,400	24,767
Total loans, net of fair value hedge basis point adjustments	4,620,900	4,457,630
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs			3,406
Commercial real estate ("CRE") | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	417,973
2022/2021	990,748	1,021,622
2021/2020	817,171	854,240
2020/2019	566,427	753,552
2019/2018	484,930	510,332
2018/2017 and Prior	1,025,160	308,265
2016 and Prior		868,099
Revolving	24,839	34,362
Revolving-Term	11,538	24,767
Total loans, net of fair value hedge basis point adjustments	4,338,786	4,375,239
Commercial real estate ("CRE") | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	28,770	2,864
2021/2020	19,872
2020/2019	88,040	19,655
2019/2018	10,484	4,653
2018/2017 and Prior	5,754	14,372
2016 and Prior		15,478
Revolving-Term	17,862
Total loans, net of fair value hedge basis point adjustments	170,782	57,022
Commercial real estate ("CRE") | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2021/2020	151	151
2020/2019	61,424	4,550
2019/2018	7,289	7,947
2018/2017 and Prior	42,468	1,131
2016 and Prior		11,590
Total loans, net of fair value hedge basis point adjustments	111,332	25,369
Acquisition, development, and construction ("ADC")
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	16,735
2022/2021	29,034	36,877
2021/2020	74,163	153,200
2020/2019	9,900	11,242
2019/2018	14,918	15,943
2018/2017 and Prior	437
2016 and Prior		2,087
Revolving	22,444	10,033
Revolving-Term	882	281
Total loans, net of fair value hedge basis point adjustments	168,513	229,663
Acquisition, development, and construction ("ADC") | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	16,735
2022/2021	17,534	36,877
2021/2020	59,202	152,543
2020/2019	9,900	11,242
2019/2018	2,665	15,943
2018/2017 and Prior	437
2016 and Prior		2,087
Revolving	22,444	10,033
Revolving-Term	225	281
Total loans, net of fair value hedge basis point adjustments	129,142	229,006
Acquisition, development, and construction ("ADC") | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	11,500
2021/2020	14,961
2019/2018	12,253
Total loans, net of fair value hedge basis point adjustments	38,714
Acquisition, development, and construction ("ADC") | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2021/2020		657
Revolving-Term	657
Total loans, net of fair value hedge basis point adjustments	657	657
Other Loans
Credit Risk Profile of Real Estate Loans [Abstract]
Total loans, net of fair value hedge basis point adjustments	5,755	7,679
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs	300	53	$ 777
Other Loans | Credit Risk Profile
Credit Risk Profile of Real Estate Loans [Abstract]
Total loans, net of fair value hedge basis point adjustments	5,755	7,679
Other Loans | Performing | Credit Risk Profile
Credit Risk Profile of Real Estate Loans [Abstract]
Total loans, net of fair value hedge basis point adjustments	5,755	7,580
Other Loans | Non-Accrual | Credit Risk Profile
Credit Risk Profile of Real Estate Loans [Abstract]
Total loans, net of fair value hedge basis point adjustments		$ 99
Excludes Other Loans
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	923,383
2022/2021	2,755,142
2021/2020	1,629,836
2020/2019	1,144,485
2019/2018	1,002,340
2018/2017 and Prior	2,458,637
Revolving	740,962
Revolving-Term	106,297
Total loans, net of fair value hedge basis point adjustments	10,761,082
Excludes Other Loans | Total real estate loans
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs 2021/2020	77
YTD Gross Charge-Offs 2020/2019	38
YTD Gross Charge-Offs 2019/2018	4,166
YTD Gross Charge-Offs 2018 and Prior/2017 and Prior	2,231
YTD Gross Charge-Offs Revolving	5,464
YTD Gross Charge-Offs Revolving-Term	3,404
YTD Gross Charge-Offs	$ 15,380