LOANS HELD FOR INVESTMENT, NET - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2020
Unpaid Principal Balance
With no related allowance recorded			$ 4,567
With related allowance recorded			12,502
Total			17,069
Recorded Investment
With no related allowance recorded			4,567
With related allowance recorded			12,502
Total			17,069
Related Allowance
Impaired Financing Receivable, Related Allowance			6,474
Average Recorded Investment
With no related allowance recorded	$ 5,832	$ 7,408
With related allowance recorded	15,961
Total		7,524
Interest Income Recognized
With no related allowance recorded		100
Total		100
Real estate
Related Allowance
Impaired Financing Receivable, Related Allowance			0
Real estate | One- to-Four Family Residential, Including Condominium and Cooperative Apartment [Member]
Average Recorded Investment
With no related allowance recorded	2,948	11
Real estate | Multifamily Residential and Residential Mixed-Use [Member]
Unpaid Principal Balance
With no related allowance recorded			1,863
Recorded Investment
With no related allowance recorded			1,863
Related Allowance
Impaired Financing Receivable, Related Allowance			0
Average Recorded Investment
With no related allowance recorded	1,355	608
Interest Income Recognized
With no related allowance recorded		9
Real estate | Commercial Real Estate and Commercial Mixed-Use [Member]
Unpaid Principal Balance
With no related allowance recorded			2,704
Recorded Investment
With no related allowance recorded			2,704
Related Allowance
Impaired Financing Receivable, Related Allowance			0
Average Recorded Investment
With no related allowance recorded	1,529	6,789
Interest Income Recognized
With no related allowance recorded		91
Commercial and industrial ("C&I") loans
Unpaid Principal Balance
With related allowance recorded			12,502
Recorded Investment
With related allowance recorded			12,502
Related Allowance
Impaired Financing Receivable, Related Allowance			$ 6,474
Average Recorded Investment
With related allowance recorded	$ 10,129	$ 116