Selected Quarterly Financial Data (Unaudited) (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, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 224,344	$ 228,772	$ 226,368	$ 222,451	$ 221,852	$ 249,815	$ 263,685	$ 254,914	$ 901,935	$ 990,266	$ 966,006
Total costs and expenses	336,807	267,783	273,628	297,769	311,866	283,279	268,793	297,525	1,175,987	1,161,463	1,242,448
Net income (loss)	$ (112,350)	$ (62,007)	$ (59,806)	$ (80,762)	$ (76,070)	$ (27,655)	$ (6,201)	$ (43,114)	$ (314,925)	$ (153,040)	$ (305,250)
Earnings (loss) per share, basic and diluted (in dollars per share)	$ (0.18)	$ (0.11)	$ (0.10)	$ (0.14)	$ (0.13)	$ (0.05)	$ (0.01)	$ (0.08)