SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)
Revenues	$ 50,841	$ 61,534	$ 60,479	$ 59,580	$ 61,898	$ 65,280	$ 62,069	$ 60,435	$ 232,434	$ 249,682	$ 125,502
Gross margin	14,346	18,939	17,987	17,500	18,154	19,612	18,568	17,092	68,772	73,426	36,522
Net income	$ 695	$ 4,278	$ 3,125	$ 2,976	$ 4,904	$ 4,115	$ 2,693	$ 2,148	$ 11,074	$ 13,860	$ 3,953
Basic earnings per share (in dollars per share)	$ 0.08	$ 0.46	$ 0.34	$ 0.32	$ 0.54	$ 0.45	$ 0.29	$ 0.24	$ 1.20	$ 1.52	$ 0.45
Diluted earnings per share (in dollars per share)	$ 0.07	$ 0.46	$ 0.34	$ 0.32	$ 0.53	$ 0.45	$ 0.29	$ 0.24	$ 1.20	$ 1.51	$ 0.45