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, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information [Abstract]
Change in fair value of contingent consideration				$ 14,400	$ 6,800					$ 28,402	$ 10,788	$ 23,931
Revenue	$ 255,187	$ 310,605	$ 278,421	262,390	202,672	$ 197,057	$ 184,101	$ 181,035		1,106,603	764,865	617,736
Operating income (loss)	9,021	31,193	12,316	(1,802)	2,428	20,290	18,123	15,350		50,728	56,191	33,133
Income (loss) from continuing operations	1,466	24,463	12,981	550	251	28,362	44,849	35,857		39,460	109,319	19,418
Loss from discontinued operations	392	(20,199)	(763)	(1,062)	(3,551)	(2,634)	(2,302)	(4,333)		(21,632)	(12,820)	(3,840)
Net income (loss) and comprehensive income (loss)	$ 1,858	$ 4,264	$ 12,218	$ (512)	$ (3,300)	$ 25,728	$ 42,547	$ 31,524		$ 17,828	$ 96,499	$ 15,578
Basic (in dollars per share)	$ 0.11	$ 1.90	$ 1.01	$ 0.04	$ 0.02	$ 2.22	$ 3.61	$ 2.97		$ 3.07	$ 8.74	$ 1.63
Diluted (in dollars per share)	0.10	1.67	0.87	0.04	0.02	2.05	3.17	2.41		2.70	7.75	1.42
Income (loss) per share from discontinued operations:
Basic (in dollars per share)	0.03	(1.57)	(0.06)	(0.08)	(0.28)	(0.21)	(0.19)	(0.36)
Diluted (in dollars per share)	0.03	(1.38)	(0.05)	(0.07)	(0.26)	(0.19)	(0.16)	(0.29)
Income per share from continuing operations:
Basic (in dollars per share)	0.14	0.33	0.95	(0.04)	(0.26)	2.01	3.43	2.61		1.39	7.72	1.30
Diluted (in dollars per share)	$ 0.13	$ 0.29	$ 0.82	$ (0.04)	$ (0.24)	$ 1.86	$ 3.01	$ 2.12		$ 1.22	$ 6.85	$ 1.14
Charitable Contribution, Total									$ 10,000	$ 10,000
Provisional estimate for remeasurement of deferred tax assets and liabilities from Tax Cuts and Jobs Act									$ 9,100			$ 9,100