BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Mar. 11, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized retained loan discounts	$ 9,000		$ 9,000		$ 7,800
Loan receivable, nonaccrual, past due period (more than)			60 days
Loans receivable, impairment and (recovery) recorded	(88)	$ 36	$ 4	$ (16)
Loan loss reserves	930		930		885
PMC Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquisition discounts at acquisition date						$ 33,900
Acquisition discount	$ 438		$ 438		$ 492