Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in net cash provided by operating activities	$ 76,776	$ 62,770
Decrease in net cash used in investing activities	325,507	(1,094,653)
Decrease in net cash provided by financing activities	(371,760)	925,972
Restricted cash	$ 2,400		$ 620
Accounting Standards Update 2016-15
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in net cash provided by operating activities		(8,100)
Decrease in net cash used in investing activities		10,100
Decrease in net cash provided by financing activities		$ (2,000)