LOANS HELD FOR INVESTMENT, NET - Allowance for Credit Losses Activity (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance		$ 83,507			$ 83,507
Provision (recovery) for credit losses	$ 892		$ 44		(2,756)	$ (1,548)
Charge-offs					(5,788)		$ (11,401)
Allowance for credit losses, Ending balance	75,646				75,646		83,507
Non-accrual with No Allowance	5,636				5,636		6,075
Non-accrual with Allowance	22,031				22,031		28,162
Reserve	16,820				16,820		22,389
Interest income on non-accrual loans held for investment
Interest income on non-accrual loans	0	0	0	$ 0
Business Loan Portfolio Segment [Member]
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	43,879	47,029	43,728	62,366	47,029	62,366	62,366
Provision (recovery) for credit losses	(542)		2,009		(2,150)	(14,045)
Charge-offs	(3,745)		(645)		(5,774)	(3,280)	(11,401)
Recoveries	108		36		595	87
Allowance for credit losses, Ending balance	39,700	43,879	45,128	43,728	39,700	45,128	47,029
Non-accrual with No Allowance	5,636				5,636		5,403
Non-accrual with Allowance	17,834				17,834		22,384
Reserve	16,131				16,131		20,812
One-to-four family residential and cooperative/condominium apartment
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	6,012	5,969	4,528	5,932	5,969	5,932	5,932
Provision (recovery) for credit losses	421		(14)		464	(1,418)
Charge-offs	(14)				(14)
Allowance for credit losses, Ending balance	6,419	6,012	4,514	4,528	6,419	4,514	5,969
Non-accrual with Allowance	3,305				3,305		3,203
Reserve	149				149		181
Multifamily residential and residential mixed-use
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	7,613	8,360	7,061	7,816	8,360	7,816	7,816
Provision (recovery) for credit losses	577		(58)		(170)	(815)
Recoveries						2
Allowance for credit losses, Ending balance	8,190	7,613	7,003	7,061	8,190	7,003	8,360
Non-owner Occupied Commercial Real Estate Portfolio Segment [Member]
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	18,076	20,153	19,180	2,131	20,153	2,131	2,131
Provision (recovery) for credit losses	364		(527)		(1,713)	16,522
Recoveries			54			54
Allowance for credit losses, Ending balance	18,440	18,076	18,707	19,180	18,440	18,707	20,153
Non-accrual with No Allowance							15
Non-accrual with Allowance	15				15		2,476
Reserve	15				15		1,297
Acquisition, development, and construction ("ADC")
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	2,515		4,758
Provision (recovery) for credit losses	43		(970)
Allowance for credit losses, Ending balance	2,558	2,515	3,788	4,758	2,558	3,788
Non-accrual with No Allowance							657
Non-accrual with Allowance	657				657
Reserve	305				305
Acquisition, development, and construction ("ADC") | Total real estate loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance		1,723		4,857	1,723	4,857	4,857
Provision (recovery) for credit losses					835	(1,069)
Allowance for credit losses, Ending balance	2,558		3,788		2,558	3,788	1,723
Other Loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	240	273	360	751	273	751	751
Provision (recovery) for credit losses	127		(74)		93	(463)
Charge-offs	(33)				(34)	(3)
Recoveries	5				7	1
Allowance for credit losses, Ending balance	339	240	286	360	339	286	273
Non-accrual with Allowance	220				220		99
Reserve	220				220		99
Includes other loans
Allowance for loan losses [Roll Forward]
Allowance for credit losses, Beginning balance	78,335	83,507	79,615	83,853	83,507	83,853	83,853
Provision (recovery) for credit losses	990		366		(2,641)	(1,288)
Charge-offs	(3,792)		(645)		(5,822)	(3,283)
Recoveries	113		90		602	144
Allowance for credit losses, Ending balance	$ 75,646	$ 78,335	$ 79,426	$ 79,615	$ 75,646	$ 79,426	$ 83,507