Condensed Financial Information of Registrant - Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating expenses
Depreciation and amortization									$ 90,036	$ 86,121	$ 52,642
General and administrative expense (excluding depreciation)									41,288	46,223	47,426
Acquisition and integration costs									614	4,704	10,319
Total operating expenses									3,442,868	5,253,536	3,328,787
Operating loss	$ (114,132)	$ 2,750	$ (25,443)	$ (181,173)	$ 59,531	$ 18,405	$ 48,621	$ 21,423	(317,998)	147,980	81,941
Other income (expense)
Interest expense and financing costs, net									(70,222)	(74,839)	(39,768)
Debt extinguishment and commitment costs									0	(11,587)	(4,224)
Other income, net									1,049	2,516	1,046
Change in value of common stock warrants									4,270	(3,199)	1,801
Equity in earnings (losses) from subsidiaries									(46,905)	(89,751)	9,464
Total other expense, net									(111,808)	(176,860)	(42,181)
Income (loss) before income taxes									(429,806)	(28,880)	39,760
Income tax benefit (expense)									20,720	69,689	(333)
Net income (loss)	$ (131,918)	$ (14,271)	$ (40,560)	$ (222,337)	$ 35,439	$ (83,891)	$ 28,169	$ 61,092	(409,086)	40,809	39,427
Parent Company
Operating expenses
Depreciation and amortization									2,900	2,969	4,092
General and administrative expense (excluding depreciation)									11,097	20,017	20,721
Acquisition and integration costs									0	28	10,118
Total operating expenses									13,997	23,014	34,931
Operating loss									(13,997)	(23,014)	(34,931)
Other income (expense)
Interest expense and financing costs, net									(4,982)	(9,952)	(10,867)
Debt extinguishment and commitment costs									0	(6,091)	0
Other income, net									(3)	2,303	1,155
Change in value of common stock warrants									4,270	(3,199)	1,801
Equity in earnings (losses) from subsidiaries									(394,197)	81,097	81,942
Total other expense, net									(394,912)	64,158	74,031
Income (loss) before income taxes									(408,909)	41,144	39,100
Income tax benefit (expense)									(177)	(335)	327
Net income (loss)									$ (409,086)	$ 40,809	$ 39,427