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LOANS HELD FOR INVESTMENT, NET - Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	$ 10,892,044		$ 10,773,428
Allowance for credit losses	85,221		71,743
Real Estate Collateral Dependent
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	26,475		11,004
Allowance for credit losses	1,395		926
Business Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses	45,026	$ 37,115	35,962	$ 36,680	$ 39,700	$ 47,029
Business Loans \| Real Estate Collateral Dependent
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	6,324		3,742
Allowance for credit losses	1,108
One-to-Four Family Residential and Cooperative/Condominium Apartment
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses	8,646	7,305	6,813	7,206	6,419	5,969
Multifamily Residential and Residential Mixed-Use
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses	12,503	12,357	7,237	7,567	8,190	8,360
Non-Owner-Occupied Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses	16,302	18,340	19,623	18,430	18,440	20,153
Non-Owner-Occupied Commercial Real Estate \| Real Estate Collateral Dependent
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans, net of fair value hedge basis point adjustments	19,494		6,605
Allowance for credit losses			621
Acquisition, development, and construction ("ADC")
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses	2,521	2,455	1,989	2,338	2,558	1,723
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	287		305
Other Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses	$ 223	$ 240	$ 119	$ 342	$ 339	$ 273