LOANS HELD FOR INVESTMENT, NET - Allowance for Credit Losses Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	$ 83,507
Provision for credit losses	2,770	$ 5,374	$ 6,212
Allowance for credit losses, Ending balance	71,743	83,507
Non-accrual with No Allowance	3,780	6,075
Non-accrual with Allowance	25,319	28,162
Reserve	14,202	22,389
Total real estate loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	43,381	47,771	28,712
Day 1 acquired PCD loans			28,753
Provision for credit losses	(718)	(4,446)	(4,077)
Charge-offs	(16)	(11,401)	(3,817)
Recoveries		56	176
Allowance for credit losses, Ending balance	42,647	43,381	47,771
Total real estate loans | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			1,976
Total real estate loans | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			(26,736)
One-to-four family residential and cooperative/condominium apartment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	5,969	5,932	644
Day 1 acquired PCD loans			2,220
Provision for credit losses	858	37	1,975
Charge-offs	(14)		(20)
Recoveries			65
Allowance for credit losses, Ending balance	6,813	5,969	5,932
Non-accrual with Allowance	3,248	3,203
Reserve	133	181
One-to-four family residential and cooperative/condominium apartment | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			1,048
One-to-four family residential and cooperative/condominium apartment | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			(1,692)
Multifamily residential and residential mixed-use
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	8,360	7,816	17,016
Day 1 acquired PCD loans			3,292
Provision for credit losses	(1,121)	542	(3,921)
Charge-offs	(2)		(391)
Recoveries		2	74
Allowance for credit losses, Ending balance	7,237	8,360	7,816
Multifamily residential and residential mixed-use | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			8,254
Multifamily residential and residential mixed-use | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			(8,762)
Commercial real estate ("CRE")
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	27,329	29,166	9,059
Day 1 acquired PCD loans			23,124
Provision for credit losses	(721)	(1,891)	(4,497)
Charge-offs			(3,406)
Recoveries		54	37
Allowance for credit losses, Ending balance	26,608	27,329	29,166
Non-accrual with No Allowance	2,298	4,915
Non-accrual with Allowance	8,229	3,417
Reserve	832	1,424
Commercial real estate ("CRE") | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			4,849
Commercial real estate ("CRE") | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			(13,908)
Acquisition, development, and construction ("ADC")
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	1,723	4,857	1,993
Day 1 acquired PCD loans			117
Provision for credit losses	266	(3,134)	2,366
Allowance for credit losses, Ending balance	1,989	1,723	4,857
Non-accrual with No Allowance		657
Non-accrual with Allowance	657
Reserve	305
Acquisition, development, and construction ("ADC") | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			381
Acquisition, development, and construction ("ADC") | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			(2,374)
Commercial and Industrial ("C&I") Loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	39,853	35,331	12,737
Day 1 acquired PCD loans			23,374
Provision for credit losses	3,464	11,786	6,016
Charge-offs	(15,364)	(11,401)	(4,984)
Recoveries	1,024	4,137	123
Allowance for credit losses, Ending balance	28,977	39,853	35,331
Non-accrual with No Allowance	1,482	503
Non-accrual with Allowance	13,185	21,443
Reserve	12,932	20,685
Commercial and Industrial ("C&I") Loans | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			1,935
Commercial and Industrial ("C&I") Loans | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			(10,802)
Other Loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	273	751	12
Day 1 acquired PCD loans			157
Provision for credit losses	129	(430)	1,364
Charge-offs	(300)	(53)	(777)
Recoveries	17	5	3
Allowance for credit losses, Ending balance	119	273	751
Non-accrual with Allowance		99
Reserve		99
Other Loans | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			8
Other Loans | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			(4)
Includes other loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	83,507	83,853	41,461
Day 1 acquired PCD loans			52,284
Provision for credit losses	2,875	6,910	3,303
Charge-offs	(15,680)	(11,454)	(9,578)
Recoveries	1,041	4,198	302
Allowance for credit losses, Ending balance	$ 71,743	$ 83,507	83,853
Includes other loans | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			3,919
Includes other loans | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance			$ (37,542)