EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
EARNINGS PER SHARE
Net income	$ 9,171	$ 8,626
Dividends paid on and earnings allocated to participating securities	(178)	(170)
Income attributable to common stock	$ 8,993	$ 8,456
Weighted average common shares outstanding, including participating securities	19,669	17,479
Weighted average participating securities (in shares)	(392)	(353)
Weighted average common shares outstanding	19,277	17,126
Basic earnings per common share (in dollars per share)	$ 0.47	$ 0.49
Income attributable to common stock	$ 8,993	$ 8,456
Weighted average common shares outstanding	19,277	17,126
Incremental shares from assumed conversions of options and restricted stock units	19	11
Weighted average common and equivalent shares outstanding	19,296	17,137
Diluted earnings per common share (in dollars per share)	$ 0.47	$ 0.49