SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of basic and diluted earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Net income	$ 14,688	$ 11,837
Weighted-average common shares outstanding	5,908	5,841
Basic earnings per share	$ 2.49	$ 2.03
Diluted earnings per share	$ 2.49	$ 2.03