EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
SHARE-BASED COMPENSATION
Net income	$ 9,917	$ 8,326	$ 13,534	$ 16,037	$ 18,243	$ 29,571
Weighted average shares outstanding - basic	28,040,802		28,546,564		28,083,602	28,651,852
Weighted average shares outstanding - diluted	28,095,230		28,729,510		28,190,132	28,847,786
Basic earnings per common share (in dollars per share)	$ 0.35		$ 0.47		$ 0.65	$ 1.03
Diluted earnings per common share (in dollars per share)	$ 0.35		$ 0.47		$ 0.65	$ 1.03
Antidilutive securities excluded from the dilutive share calculation (in shares)	0		0		0	0
Stock Option
SHARE-BASED COMPENSATION
Dilutive effect of share-based compensation arrangements	54,428		182,946		106,530	195,934