LOANS HELD FOR INVESTMENT, NET - Allowance for Credit Losses Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	$ 83,853	$ 41,461	$ 28,441
Day 1 acquired PCD loans		52,284
Provision (credit) for credit losses	6,910	3,303	26,165
Charge-offs	(11,454)	(9,578)	(13,309)
Recoveries	4,198	302	164
Allowance for credit losses, Ending balance	83,507	83,853	41,461
Non-accrual with No Allowance	6,075
Reserve	22,389
Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	(3,919)
Allowance for credit losses, Ending balance		(3,919)
Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	37,542
Allowance for credit losses, Ending balance		37,542
Total real estate loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	47,771	28,712	15,555
Day 1 acquired PCD loans		28,753
Provision (credit) for credit losses	(4,446)	(4,077)	16,234
Charge-offs		(3,817)	(3,207)
Recoveries	56	176	130
Allowance for credit losses, Ending balance	43,381	47,771	28,712
Total real estate loans | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	(1,976)
Allowance for credit losses, Ending 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
Allowance for credit losses, Ending balance		26,736
One-to-four family residential and cooperative/condominium apartment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	5,932	644	269
Day 1 acquired PCD loans		2,220
Provision (credit) for credit losses	37	1,975	386
Charge-offs		(20)	(11)
Recoveries		65
Allowance for credit losses, Ending balance	5,969	5,932	644
Non-accrual with Allowance	3,203
Reserve	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
Allowance for credit losses, Ending 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
Allowance for credit losses, Ending balance		1,692
Multifamily residential and residential mixed-use
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	7,816	17,016	10,142
Day 1 acquired PCD loans		3,292
Provision (credit) for credit losses	542	(3,921)	9,934
Charge-offs		(391)	(3,190)
Recoveries	2	74	130
Allowance for credit losses, Ending balance	8,360	7,816	17,016
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)
Allowance for credit losses, Ending 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
Allowance for credit losses, Ending balance		8,762
Acquisition, development, and construction
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	4,857	1,993	1,244
Day 1 acquired PCD loans		117
Provision (credit) for credit losses	(3,134)	2,366	749
Allowance for credit losses, Ending balance	1,723	4,857	1,993
Non-accrual with No Allowance	657
Acquisition, development, and construction | Cumulative Effect, CECL Adoption, Adjustment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	381
Allowance for credit losses, Ending balance		381
Acquisition, development, and construction | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	2,374
Allowance for credit losses, Ending balance		2,374
Commercial real estate ("CRE")
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	29,166	9,059	3,900
Day 1 acquired PCD loans		23,124
Provision (credit) for credit losses	(1,891)	(4,497)	5,165
Charge-offs		(3,406)	(6)
Recoveries	54	37
Allowance for credit losses, Ending balance	27,329	29,166	9,059
Non-accrual with No Allowance	4,915
Non-accrual with Allowance	3,417
Reserve	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
Allowance for credit losses, Ending 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
Allowance for credit losses, Ending balance		13,908
Commercial and Industrial ("C&I") Loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	35,331	12,737	12,870
Day 1 acquired PCD loans		23,374
Provision (credit) for credit losses	11,786	6,016	9,928
Charge-offs	(11,401)	(4,984)	(10,095)
Recoveries	4,137	123	34
Allowance for credit losses, Ending balance	39,853	35,331	12,737
Non-accrual with No Allowance	503
Non-accrual with Allowance	21,443
Reserve	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)
Allowance for credit losses, Ending 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
Allowance for credit losses, Ending balance		10,802
Other Loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	751	12	16
Day 1 acquired PCD loans		157
Provision (credit) for credit losses	(430)	1,364	3
Charge-offs	(53)	(777)	(7)
Recoveries	5	3
Allowance for credit losses, Ending balance	273	751	$ 12
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)
Allowance for credit losses, Ending balance		(8)
Other Loans | Cumulative Effect, CECL Adoption, Adjusted Balance
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	$ 4
Allowance for credit losses, Ending balance		$ 4