New Accounting Standards New Accounting Standards Adopted (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Dec. 31, 2017	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle
Change in net cash used in investing activities	$ (391,449)	$ 61,708
Change in net cash provided by operating activities	229,662	160,315
Change in cash, cash equivalents and restricted cash	$ 680,779	224,512	$ 212,824	$ 275,949
Restricted cash guidance
New Accounting Pronouncements or Change in Accounting Principle
Change in net cash used in investing activities		23,624
Change in net cash provided by operating activities		(16,428)
Change in cash, cash equivalents and restricted cash		$ 37,883		$ 77,709