LOANS HELD FOR INVESTMENT, NET - Loan Categories (Details) - USD ($) $ in Thousands	1 Months Ended
	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loans held for investment, net:
Total Loans		$ 10,566,831	$ 9,244,661
Principal balances outstanding		10,566,831	9,244,661
Allowance for loan losses		(83,507)	(83,853)	$ (41,461)	$ (28,441)
Total loans held for investment, net		$ 10,483,324	9,160,808
Small Business Administration ("SBA") Paycheck Protection Program ("PPP") [Member]
Loans held for investment, net:
Loan and leases carry guarantee rate		100.00%
Total real estate loans
Loans held for investment, net:
Total Loans		$ 9,487,440	8,294,204
Allowance for loan losses		(43,381)	(47,771)	(28,712)	(15,555)
One-to-four family residential and cooperative/condominium apartment
Loans held for investment, net:
Total Loans		773,321	669,282
Allowance for loan losses		(5,969)	(5,932)	(644)	(269)
Multifamily residential and residential mixed-use
Loans held for investment, net:
Total Loans		4,026,826	3,356,346
Allowance for loan losses		(8,360)	(7,816)	(17,016)	(10,142)
Commercial real estate ("CRE")
Loans held for investment, net:
Total Loans		4,457,630	3,945,948
Allowance for loan losses		(27,329)	(29,166)	(9,059)	(3,900)
Acquisition, development, and construction
Loans held for investment, net:
Total Loans		229,663	322,628
Allowance for loan losses		(1,723)	(4,857)	(1,993)	(1,244)
Commercial and Industrial ("C&I") Loans
Loans held for investment, net:
Total Loans		1,071,712	933,559
Allowance for loan losses		(39,853)	(35,331)	(12,737)	(12,870)
Commercial and Industrial ("C&I") Loans | Small Business Administration ("SBA") Paycheck Protection Program ("PPP") [Member]
Loans held for investment, net:
Principal balances outstanding		5,800	66,000
Gain recorded on sale of SBA loans	$ 20,700
Sold amount	$ 596,200
Other Loans
Loans held for investment, net:
Total Loans		7,679	16,898
Allowance for loan losses		$ (273)	$ (751)	$ (12)	$ (16)