QUARTERLY FINANCIAL INFORMATION QUARTERLY FINANCIAL INFORMATION (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
Revenue	$ 78,341	$ 69,804	$ 55,136	$ 50,935	$ 43,864	$ 41,306	$ 42,144	$ 40,036	$ 254,216	$ 167,350	$ 139,240
Operating income (loss)	8,248	7,773	6,775	5,718	1,712	554	2,600	(5,835)	28,514	(969)	(1,107)
Income (loss) from continuing operations	32,081	7,383	6,439	5,413	2,109	555	2,683	(5,834)	51,316	(487)	(673)
Income (loss) from discontinued operations	(31)	(1,295)	(1,717)	(226)	13,528	(174)	(2,931)	(574)	(3,269)	9,849	4,620
Net income (loss) and comprehensive income (loss)	$ 32,050	$ 6,088	$ 4,722	$ 5,187	$ 15,637	$ 381	$ (248)	$ (6,408)	$ 48,047	$ 9,362	$ 3,947
Income (loss) per share from continuing operations:
Basic (in dollars per share)	$ 2.69	$ 0.65	$ 0.57	$ 0.48	$ 0.19	$ 0.05	$ 0.24	$ (0.52)	$ 4.46	$ (0.04)	$ (0.06)
Diluted (in dollars per share)	2.47	0.59	0.52	0.44	0.18	0.05	0.23	(0.52)	4.09	(0.04)	(0.06)
Income (loss) per share from discontinued operations:
Basic (in dollars per share)	0.00	(0.11)	(0.15)	(0.02)	1.21	(0.02)	(0.26)	(0.05)
Diluted (in dollars per share)	0.00	(0.10)	(0.14)	(0.02)	1.12	(0.01)	(0.25)	(0.05)
Net income (loss) per share:
Basic (in dollars per share)	2.69	0.53	0.41	0.46	1.39	0.03	(0.02)	(0.58)	4.17	0.84	0.36
Diluted (in dollars per share)	$ 2.47	$ 0.49	$ 0.38	$ 0.43	$ 1.30	$ 0.03	$ (0.02)	$ (0.58)	$ 3.83	$ 0.84	$ 0.36