Goodwill - Goodwill Activity (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 9,835,400	$ 9,835,400	$ 9,835,400
Accumulated impairment losses, beginning of period	(5,322,104)	(4,852,104)	(4,852,104)
Goodwill, net, beginning of period	4,513,296	4,983,296	4,983,296
Impairment losses	(2,185,000)	$ 0	(470,000)	$ 0
Goodwill, end of period	9,835,400		9,835,400
Accumulated impairment losses, end of period	(7,507,104)		(5,322,104)
Goodwill, net, end of period	$ 2,328,296		$ 4,513,296