EARNINGS PER COMMON SHARE - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 15,597	$ 11,407	$ 41,380	$ 31,517
Basic:
Weighted average shares outstanding (in shares)	37,339	37,056	37,259	37,023
Weighted average shares outstanding (in dollars per share)	$ 0.42	$ 0.31	$ 1.11	$ 0.85
Diluted:
Effect of dilutive securities - options (in shares)	387	276	393	250
Weighted average shares outstanding, Total (in shares)	37,726	37,332	37,652	37,273
Weighted average shares outstanding, Total (in dollars per share)	$ 0.41	$ 0.31	$ 1.10	$ 0.85