EARNINGS PER COMMON SHARE - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 16,421	$ 12,898	$ 25,783	$ 20,110
Basic:
Weighted average shares outstanding (in shares)	37,274	37,023	37,219	37,007
Weighted average shares outstanding (in dollars per share)	$ 0.44	$ 0.35	$ 0.69	$ 0.54
Diluted:
Effect of dilutive securities - options (in shares)	372	241	394	227
Weighted average shares outstanding, Total (in shares)	37,646	37,264	37,613	37,234
Weighted average shares outstanding, Total (in dollars per share)	$ 0.44	$ 0.35	$ 0.69	$ 0.54