EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
EARNINGS PER SHARE
Net income	$ 15,491	$ 13,220	$ 23,534	$ 22,463
Basic
Weighted average basic shares outstanding	22,006	21,867	21,997	21,835
Earnings per share (in dollars per share)	$ 0.70	$ 0.60	$ 1.07	$ 1.03
Diluted
Net income, diluted	$ 15,491	$ 13,220	$ 23,534	$ 22,463
Dilutive effect of share-based awards (in shares)	202	157	206	156
Weighted average diluted shares outstanding	22,208	22,024	22,203	21,991
Earnings per share (in dollars per share)	$ 0.70	$ 0.60	$ 1.06	$ 1.02
Anti-dilutive shares excluded from calculation	92	58	86	76