LOANS HELD FOR INVESTMENT, NET - Credit Quality Indicators (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Credit Risk Profile of Real Estate Loans [Abstract]
Total Loans	$ 10,731,845	$ 10,566,831
Principal balances outstanding	3,325
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	38	2,088
YTD Gross Charge-Offs 2018 and Prior/2017 and Prior	1,991	2,414
YTD Gross Charge-Offs Revolving		1,460
YTD Gross Charge-Offs Revolving-Term		242
YTD Gross Charge-Offs	2,029	11,401
Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	369,604
2022/2021	2,838,002	2,845,426
2021/2020	1,721,953	1,733,872
2020/2019	1,094,865	1,196,053
2019/2018	1,005,728	1,024,753
2018/2017 and Prior	2,593,728	522,005
2016 and Prior		2,175,148
Revolving		726,711
Revolving-Term	60,821	59,850
Total Loans	10,398,540	10,283,818
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	713,839
Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	6,244	6,634
2021/2020	4,893
2020/2019	67,562	20,549
2019/2018	20,150	17,365
2018/2017 and Prior	49,956	16,628
2016 and Prior		31,664
Revolving		9,641
Revolving-Term	7,426	1,204
Total Loans	171,532	103,685
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	15,301
Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	98
2022/2021	5,454	5,242
2021/2020	2,888	2,052
2020/2019	21,181	23,234
2019/2018	11,440	19,143
2018/2017 and Prior	82,003	22,819
2016 and Prior		66,232
Revolving		11,290
Revolving-Term	10,015	10,505
Total Loans	145,460	160,517
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	12,382
Doubtful
Credit Risk Profile of Real Estate Loans [Abstract]
2019/2018	8,332	8,332
2018/2017 and Prior	809	752
2016 and Prior		2,048
Total Loans	9,141	11,132
Total real estate loans
Credit Risk Profile of Real Estate Loans [Abstract]
Total Loans	9,649,743	9,487,440
Excludes Other Loans
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	369,702
2022/2021	2,849,700	2,857,302
2021/2020	1,729,734	1,735,924
2020/2019	1,183,608	1,239,836
2019/2018	1,045,650	1,069,593
2018/2017 and Prior	2,726,496	562,204
2016 and Prior		2,275,092
Revolving	741,522	747,642
Revolving-Term	78,262	71,559
Total Loans	10,724,673	10,559,152
One-to-four family residential and cooperative/condominium apartment
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	43,242
2022/2021	223,185	225,031
2021/2020	106,629	108,185
2020/2019	72,838	73,758
2019/2018	65,785	66,742
2018/2017 and Prior	235,288	67,180
2016 and Prior		176,292
Revolving	36,239	41,751
Revolving-Term	16,116	14,382
Total Loans	799,321	773,321
Principal balances outstanding	2,850
One-to-four family residential and cooperative/condominium apartment | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	43,242
2022/2021	223,185	225,031
2021/2020	105,682	108,185
2020/2019	71,817	72,732
2019/2018	64,559	65,515
2018/2017 and Prior	223,911	66,038
2016 and Prior		164,338
Revolving		41,172
Revolving-Term	14,027	12,563
Total Loans	782,503	755,574
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	36,080
One-to-four family residential and cooperative/condominium apartment | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2018/2017 and Prior	765	735
2016 and Prior		1,175
Revolving		579
Revolving-Term	1,140	726
Total Loans	2,064	3,215
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	159
One-to-four family residential and cooperative/condominium apartment | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2021/2020	947
2020/2019	1,021	1,026
2019/2018	1,226	1,227
2018/2017 and Prior	10,612	407
2016 and Prior		10,779
Revolving-Term	949	1,093
Total Loans	14,754	14,532
Multifamily residential and residential mixed-use
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	137,533
2022/2021	1,378,920	1,386,549
2021/2020	600,989	582,393
2020/2019	324,128	328,718
2019/2018	411,034	414,117
2018/2017 and Prior	1,249,490	147,385
2016 and Prior		1,155,080
Revolving	11,981	12,584
Revolving-Term	4,364
Total Loans	4,118,439	4,026,826
Multifamily residential and residential mixed-use | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	137,533
2022/2021	1,378,920	1,386,549
2021/2020	596,720	582,393
2020/2019	295,172	316,424
2019/2018	396,885	395,933
2018/2017 and Prior	1,182,588	127,074
2016 and Prior		1,107,281
Revolving		12,584
Revolving-Term	4,364
Total Loans	4,004,163	3,928,238
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	11,981
Multifamily residential and residential mixed-use | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2021/2020	4,269
2020/2019	18,190
2019/2018	14,149	11,183
2018/2017 and Prior	19,272
2016 and Prior		14,168
Total Loans	55,880	25,351
Multifamily residential and residential mixed-use | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2020/2019	10,766	12,294
2019/2018		7,001
2018/2017 and Prior	47,630	20,311
2016 and Prior		33,631
Total Loans	58,396	73,237
Commercial real estate ("CRE")
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	168,749
2022/2021	1,017,934	1,024,486
2021/2020	848,765	854,391
2020/2019	736,634	777,757
2019/2018	508,291	522,932
2018/2017 and Prior	1,177,399	323,768
2016 and Prior		895,167
Revolving	29,949	34,362
Revolving-Term	23,247	24,767
Total Loans	4,510,968	4,457,630
Commercial real estate ("CRE") | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	168,749
2022/2021	1,015,122	1,021,622
2021/2020	848,614	854,240
2020/2019	684,193	753,552
2019/2018	496,165	510,332
2018/2017 and Prior	1,136,286	308,265
2016 and Prior		868,099
Revolving		34,362
Revolving-Term	23,247	24,767
Total Loans	4,402,325	4,375,239
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	29,949
Commercial real estate ("CRE") | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	2,812	2,864
2020/2019	47,905	19,655
2019/2018	4,630	4,653
2018/2017 and Prior	27,888	14,372
2016 and Prior		15,478
Total Loans	83,235	57,022
Commercial real estate ("CRE") | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2021/2020	151	151
2020/2019	4,536	4,550
2019/2018	7,496	7,947
2018/2017 and Prior	13,225	1,131
2016 and Prior		11,590
Total Loans	25,408	25,369
Acquisition, development, and construction
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	42,427	36,877
2021/2020	137,087	153,200
2020/2019	7,647	11,242
2019/2018	15,744	15,943
2018/2017 and Prior	609
2016 and Prior		2,087
Revolving	17,233	10,033
Revolving-Term	268	281
Total Loans	221,015	229,663
Acquisition, development, and construction | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	42,427	36,877
2021/2020	136,430	152,543
2020/2019	7,647	11,242
2019/2018	15,744	15,943
2018/2017 and Prior	609
2016 and Prior		2,087
Revolving		10,033
Revolving-Term	268	281
Total Loans	220,358	229,006
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	17,233
Acquisition, development, and construction | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2021/2020	657	657
Total Loans	657	657
Commercial and Industrial ("C&I") Loans
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	20,178
2022/2021	187,234	184,359
2021/2020	36,264	37,755
2020/2019	42,361	48,361
2019/2018	44,796	49,859
2018/2017 and Prior	63,710	23,871
2016 and Prior		46,466
Revolving	646,120	648,912
Revolving-Term	34,267	32,129
Total Loans	1,074,930	1,071,712
Principal balances outstanding	475
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	38	2,088
YTD Gross Charge-Offs 2018 and Prior/2017 and Prior	1,991	2,414
YTD Gross Charge-Offs Revolving		1,460
YTD Gross Charge-Offs Revolving-Term		242
YTD Gross Charge-Offs	2,029	11,401
Commercial and Industrial ("C&I") Loans | Pass
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	20,080
2022/2021	178,348	175,347
2021/2020	34,507	36,511
2020/2019	36,036	42,103
2019/2018	32,375	37,030
2018/2017 and Prior	50,334	20,628
2016 and Prior		33,343
Revolving		628,560
Revolving-Term	18,915	22,239
Total Loans	989,191	995,761
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	618,596
Commercial and Industrial ("C&I") Loans | Special Mention
Credit Risk Profile of Real Estate Loans [Abstract]
2022/2021	3,432	3,770
2021/2020	624
2020/2019	1,467	894
2019/2018	1,371	1,529
2018/2017 and Prior	2,031	1,521
2016 and Prior		843
Revolving		9,062
Revolving-Term	6,286	478
Total Loans	30,353	18,097
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	15,142
Commercial and Industrial ("C&I") Loans | Substandard
Credit Risk Profile of Real Estate Loans [Abstract]
2023/2022	98
2022/2021	5,454	5,242
2021/2020	1,133	1,244
2020/2019	4,858	5,364
2019/2018	2,718	2,968
2018/2017 and Prior	10,536	970
2016 and Prior		10,232
Revolving		11,290
Revolving-Term	9,066	9,412
Total Loans	46,245	46,722
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
YTD Gross Charge-Offs Revolving	12,382
Commercial and Industrial ("C&I") Loans | Doubtful
Credit Risk Profile of Real Estate Loans [Abstract]
2019/2018	8,332	8,332
2018/2017 and Prior	809	752
2016 and Prior		2,048
Total Loans	9,141	11,132
Other Loans
Credit Risk Profile of Real Estate Loans [Abstract]
Total Loans	7,172	7,679
Other Loans | Credit Risk Profile
Credit Risk Profile of Real Estate Loans [Abstract]
Total Loans	7,172
Other Loans | Performing
Credit Risk Profile of Real Estate Loans [Abstract]
Total Loans		7,580
Other Loans | Performing | Credit Risk Profile
Credit Risk Profile of Real Estate Loans [Abstract]
Total Loans	7,073
Other Loans | Non-Accrual
Credit Risk Profile of Real Estate Loans [Abstract]
Total Loans		$ 99
Other Loans | Non-Accrual | Credit Risk Profile
Credit Risk Profile of Real Estate Loans [Abstract]
Total Loans	$ 99