LOANS HELD FOR INVESTMENT, NET - Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	$ 10,773,428	$ 10,566,831
Allowance for credit losses	71,743	83,507
Total real estate loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	9,694,144	9,487,440
Allowance for credit losses	42,647	43,381	$ 47,771	$ 28,712
Real Estate Collateral Dependent | Total real estate loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	11,004	8,997
Allowance for credit losses	926	1,297
One-to-four family residential and cooperative/condominium apartment
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	887,555	773,321
Allowance for credit losses	6,813	5,969	5,932	644
Multifamily residential and residential mixed-use
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	4,017,176	4,026,826
Allowance for credit losses	7,237	8,360	7,816	17,016
Commercial real estate ("CRE")
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	4,620,900	4,457,630
Allowance for credit losses	26,608	27,329	29,166	9,059
Commercial real estate ("CRE") | Real Estate Collateral Dependent
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	8,903	7,391
Allowance for credit losses	621	1,297
Acquisition, development, and construction ("ADC")
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	168,513	229,663
Allowance for credit losses	1,989	1,723	4,857	1,993
Acquisition, development, and construction ("ADC") | Real Estate Collateral Dependent
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	657	657
Allowance for credit losses	305
Commercial and Industrial ("C&I") Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	1,066,938	1,071,712
Allowance for credit losses	28,977	39,853	35,331	12,737
Commercial and Industrial ("C&I") Loans | Real Estate Collateral Dependent
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	1,444	949
Other Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	5,755	7,679
Allowance for credit losses	$ 119	$ 273	$ 751	$ 12