EARNINGS PER SHARE - (Details) - $ / shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Shares
Basic (in shares)	17,997	17,821	17,967	17,795
Effect of dilutive stock options (in shares)	669	748	676	761
Diluted (in shares)	18,666	18,569	18,643	18,556
Per Share Amount
Basic (in dollars per share)	$ 0.52	$ 0.52	$ 0.91	$ 0.90
Effect of dilutive stock options (in dollars per share)	(0.02)	(0.02)	(0.03)	(0.04)
Diluted (in dollars per share)	$ 0.50	$ 0.50	$ 0.88	$ 0.86