INTANGIBLE ASSETS AND GOODWILL - Changes in Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill balance before cumulative loss on impairment as of January 1,		$ 1,024,467		$ 1,024,467	$ 982,663
Accumulated loss on impairment as of January 1,		(980,547)		(980,547)	$ (443,194)
Goodwill beginning balance after cumulative loss on impairment as of January 1,	$ 43,920			539,469
Loss on impairment during year	0	(537,400)		(537,353)
Dispositions	0			(4,862)
Acquisitions	0			46,666
Measurement period adjustments to acquired goodwill	(28)		$ (28)	0
Ending period balance	$ 43,892	$ 43,920	$ 43,892	$ 43,920