QUARTERLY FINANCIAL INFORMATION (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information [Abstract]
Revenue	$ 160,954	$ 171,494	$ 152,773	$ 132,515	$ 100,841	$ 94,558	$ 94,290	$ 94,713	$ 617,736	$ 384,402	$ 254,216
Operating income (loss)	(175)	17,455	8,969	6,884	13,402	14,150	12,715	11,845	33,133	52,112	28,514
Income (loss) from continuing operations	(6,518)	10,131	8,007	7,798	8,021	7,280	9,002	6,905	19,418	31,208	51,316
Income (loss) from discontinued operations	(1,208)	(1,011)	(689)	(932)	(697)	(664)	(1,150)	(1,203)	(3,840)	(3,714)	(3,269)
Net income (loss) and comprehensive income (loss)	$ (7,726)	$ 9,120	$ 7,318	$ 6,866	$ 7,324	$ 6,616	$ 7,852	$ 5,702	$ 15,578	$ 27,494	$ 48,047
Basic (in dollars per share)	$ (0.54)	$ 0.84	$ 0.67	$ 0.66	$ 0.68	$ 0.62	$ 0.76	$ 0.58	$ 1.63	$ 2.64	$ 4.46
Diluted (in dollars per share)	(0.54)	0.74	0.59	0.58	0.63	0.57	0.71	0.54	1.42	2.44	4.09
Income (loss) per share from discontinued operations:
Basic (in dollars per share)	(0.10)	(0.08)	(0.06)	(0.08)	(0.06)	(0.06)	(0.10)	(0.10)
Diluted (in dollars per share)	(0.10)	(0.07)	(0.05)	(0.07)	(0.05)	(0.05)	(0.09)	(0.09)
Income per share from continuing operations:
Basic (in dollars per share)	(0.64)	0.76	0.61	0.58	0.62	0.56	0.67	0.48	1.30	2.33	4.17
Diluted (in dollars per share)	$ (0.64)	$ 0.66	$ 0.54	$ 0.51	$ 0.57	$ 0.52	$ 0.62	$ 0.44	$ 1.14	$ 2.15	$ 3.83
Charitable Contribution	$ 10,000
Provisional estimate for remeasurement of deferred tax assets and liabilities from Tax Cuts and Jobs Act	$ 9,100								$ 9,062	$ 0	$ 0