INTANGIBLE ASSETS AND GOODWILL - Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill balance before cumulative loss			$ 982,663	$ 988,056
Accumulated loss on impairment			(443,194)	(126,056)
Goodwill			539,469	862,000
Loss on impairment	$ (537,400)	$ (317,100)	(537,353)	(317,138)	$ (441)
Disposition			(4,862)	(8,623)
Acquisition			46,666	24,728
Measurement period adjustments to acquired goodwill			0	(21,498)
Goodwill	43,920	539,469	43,920	539,469	862,000
Goodwill balance before cumulative loss	1,024,467	982,663	1,024,467	982,663	988,056
Accumulated loss on impairment	$ (980,547)	$ (443,194)	$ (980,547)	$ (443,194)	$ (126,056)