UNAUDITED QUARTERLY FINANCIAL INFORMATION (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
UNAUDITED QUARTERLY FINANCIAL INFORMATION [Abstract]
Revenue	$ 73,915	$ 72,594	$ 63,569	$ 63,263	$ 70,113	$ 70,078	$ 61,120	$ 61,889	$ 273,342	$ 263,200	$ 261,853
Net (loss) income	$ 9,206	$ 1,340	$ (3,064)	$ (5,467)	$ 5,033	$ (600)	$ (4,104)	$ (6,874)	$ 2,015	$ (6,545)	$ (11,484)
Basic [Abstract]
Net (loss) earnings per share (in dollars per share)	$ 0.33	$ 0.05	$ (0.12)	$ (0.22)	$ 0.21	$ (0.02)	$ (0.17)	$ (0.28)	$ 0.08	$ (0.27)	$ (0.48)
Diluted [Abstract]
Net (loss) earnings per share (in dollars per share)	$ 0.33	$ 0.05	$ (0.12)	$ (0.22)	$ 0.20	$ (0.02)	$ (0.17)	$ (0.28)	$ 0.08	$ (0.27)	$ (0.48)
Weighted average number of common shares outstanding [Abstract]
Basic (in shares)	24,563,000	24,563,000	24,555,000	24,534,000	24,533,000	24,533,000	24,486,000	24,138,000	24,554,033	24,423,479	23,906,395
Diluted (in shares)	24,563,000	24,608,000	24,555,000	24,534,000	24,562,000	24,533,000	24,486,000	24,138,000	24,554,033	24,423,479	23,906,395