SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Anti-dilution (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Anti-dilutive common shares not included for computation of earnings per share
Basic weighted-average shares of common stock outstanding	15,983,000	15,988,000	16,138,000
Stock options (in shares)		54,000	72,000
Diluted weighted-average shares of common stock outstanding	15,983,000	16,042,000	16,210,000
Stock options
Anti-dilutive common shares not included for computation of earnings per share
Anti-dilutive potential shares excluded from the computation of diluted weighted average shares outstanding (in shares)	8,800	5,000	7,000