(LOSS) INCOME PER COMMON SHARE - Calculations of Basic and Diluted Loss per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net (loss) income – basic	$ (13,519)	$ (11,513)	$ (4,867)	$ 5,948	$ (6,057)	$ (11,598)	$ (29,899)	$ (11,707)
Weighted-average shares outstanding - basic (in shares)	20,429			20,357			20,494	19,123
Effect of dilutive securities:
Weighted-average shares outstanding - diluted (in shares)	20,429			20,481			20,494	19,123
Basic (loss) income per common share (usd per share)	$ (0.66)			$ 0.29			$ (1.46)	$ (0.61)
Diluted (loss) income per common share (usd per share)	$ (0.66)			$ 0.29			$ (1.46)	$ (0.61)
Antidilutive securities (in shares)	2,128			1,361			2,246	1,746
Stock options and other stock awards
Effect of dilutive securities:
Stock options and other stock awards (in shares)	0			124			0	0