Description of Business and Basis of Presentation (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Reduction to cash and cash equivalents	$ (1,696,903)	$ (984,748)	$ (764,522)	$ (640,190)
Increase (decrease) in net cash provided by operating activities	330,577	296,359
Increase (decrease) in net cash used in financing activities	$ 715,062	116,061
Capitalization period	8 years
Estimated amortization period, less than	1 year
Accounting Standards Update 2016-09
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Increase (decrease) in net cash provided by operating activities		5,000
Increase (decrease) in net cash used in financing activities		5,000
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Reduction to cash and cash equivalents		$ 7,000	$ 10,000