EARNINGS PER SHARE - Computation of EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
EARNINGS PER SHARE
Net income	$ 13,864	$ 6,547	$ 6,743	$ 12,073	$ (6,916)	$ 9,443	$ 8,841	$ 9,171	$ 39,227	$ 20,539	$ 35,491
Dividends paid on and earnings allocated to participating securities									(853)	(415)	(732)
Income attributable to common stock									$ 38,374	$ 20,124	$ 34,759
Weighted average common shares outstanding, including participating securities									19,875	19,759	17,670
Weighted average participating securities (in shares)									(434)	(404)	(366)
Weighted average common shares outstanding									19,441	19,355	17,304
Basic earnings per common share (in dollars per share)	$ 0.70	$ 0.33	$ 0.34	$ 0.61	$ (0.35)	$ 0.48	$ 0.45	$ 0.47	$ 1.97	$ 1.04	$ 2.01
Income attributable to common stock									$ 38,374	$ 20,124	$ 34,759
Impact of assumed conversions - interest on 8.5% trust preferred securities									0	0	878
Income attributable to common stock including assumed conversions									$ 38,374	$ 20,124	$ 35,637
Weighted average common shares outstanding									19,441	19,355	17,304
Incremental shares from assumed conversions of options and restricted stock units									27	24	13
Incremental shares from assumed conversions of 8.5% trust preferred securities									0	0	534
Weighted average common and equivalent shares outstanding (in shares)									19,468	19,379	17,851
Diluted earnings per common share (in dollars per share)	$ 0.70	$ 0.33	$ 0.34	$ 0.61	$ (0.35)	$ 0.48	$ 0.45	$ 0.47	$ 1.97	$ 1.04	$ 2.00