INCOME TAXES - Unrecognized tax benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
INCOME TAXES
Unrecognized tax benefits at beginning of year	$ 844	$ 844
Additions for tax positions of prior years	174
Unrecognized tax benefits at end of year	1,018	$ 844
Amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate	$ 1,000