EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
EARNINGS PER SHARE
Net income	$ 6,743	$ 8,841	$ 18,816	$ 18,012
Dividends paid on and earnings allocated to participating securities	(148)	(182)	(405)	(360)
Income attributable to common stock	$ 6,595	$ 8,659	$ 18,411	$ 17,652
Weighted average common shares outstanding, including participating securities	19,884	19,781	19,859	19,725
Weighted average participating securities (in shares)	(445)	(410)	(433)	(401)
Weighted average common shares outstanding	19,439	19,371	19,426	19,324
Basic earnings per common share (in dollars per share)	$ 0.34	$ 0.45	$ 0.95	$ 0.91
Income attributable to common stock	$ 6,595	$ 8,659	$ 18,411	$ 17,652
Impact of assumed conversions - interest on 8.5% trust preferred securities	0	0	0	32
Income attributable to common stock including assumed conversions	$ 6,595	$ 8,659	$ 18,411	$ 17,684
Weighted average common shares outstanding	19,439	19,371	19,426	19,324
Incremental shares from assumed conversions of options and restricted stock units	29	23	27	20
Incremental shares from assumed conversions of 8.5% trust preferred securities	0	0	0	35
Weighted average common and equivalent shares outstanding (in shares)	19,468	19,394	19,453	19,379
Diluted earnings per common share (in dollars per share)	$ 0.34	$ 0.45	$ 0.95	$ 0.91