QUARTERLY FINANCIAL DATA (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net revenues	$ 38,205	$ 38,525	$ 31,337	$ 20,555	$ 18,035	$ 19,972	$ 19,516	$ 18,799	$ 128,622	$ 76,322	$ 55,970
Total operating expenses	36,907	30,604	26,143	14,889	11,767	11,521	11,102	9,232	108,543	43,622	35,964
Operating income	1,298	7,921	5,194	5,666	6,268	8,451	8,414	9,567	20,079	32,700	20,006
Net income/(loss)	$ (1,080)	$ 2,543	$ 1,125	$ 1,346	$ 2,876	$ 4,559	$ 3,571	$ 4,369	$ 3,934	$ 15,375	$ 28,747
Basic and diluted earnings/(loss) per share:
Basic earnings/(loss) per share (in dollars per share)	$ (0.09)	$ 0.22	$ 0.10	$ 0.12	$ 0.25	$ 0.40	$ 0.31	$ 0.38	$ 0.34	$ 1.34	$ 2.61
Diluted earnings/(loss) per share (in dollars per share)	$ (0.09)	$ 0.22	$ 0.10	$ 0.12	$ 0.25	$ 0.39	$ 0.31	$ 0.38	$ 0.34	$ 1.32	$ 2.59