LOANS HELD FOR INVESTMENT, NET - Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	$ 10,731,845	$ 10,566,831
Allowance for credit losses	78,335	83,507
Commercial real estate ("CRE")
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	4,510,968	4,457,630
Allowance for credit losses	24,478	27,329	$ 28,645	$ 29,166
Acquisition, development, and construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	221,015	229,663
Allowance for credit losses	2,515	1,723	4,758	4,857
Commercial and Industrial ("C&I") Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	1,074,930	1,071,712
Allowance for credit losses	37,477	39,853	34,263	35,331
Total real estate loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	9,649,743	9,487,440
Allowance for credit losses	40,618	43,381	$ 44,992	$ 47,771
Real Estate Collateral Dependent | Commercial real estate ("CRE")
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	7,112	7,391
Allowance for credit losses	860	1,297
Real Estate Collateral Dependent | Acquisition, development, and construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	657	657
Allowance for credit losses	305
Real Estate Collateral Dependent | Commercial and Industrial ("C&I") Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	945	949
Real Estate Collateral Dependent | Total real estate loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total Loans	8,714	8,997
Allowance for credit losses	$ 1,165	$ 1,297