FAIR VALUES OF FINANCIAL INSTRUMENTS - Gains and (Losses) on Non-Recurring Assets (Details) - Nonrecurring - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Individually evaluated loans: | Single family residential mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains and (losses) recognized on assets measured at fair value	$ (169)	$ (490)	$ (115)
Individually evaluated loans: | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains and (losses) recognized on assets measured at fair value	(10,292)	0	(1,752)
Individually evaluated loans: | SBA
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains and (losses) recognized on assets measured at fair value	(2,052)	(46)	(1,048)
Individually evaluated loans: | Other consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains and (losses) recognized on assets measured at fair value	0	(88)	(141)
Single family residential mortgage | Other real estate owned:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains and (losses) recognized on assets measured at fair value	$ 0	$ (104)	$ 229