Organization, Basis of Presentation and Significant Accounting Policies (Details 4) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	$ 625,297	$ 575,656
Net cash used in investing activities	(316,681)	(253,724)
Net cash used in financing activities	(160,625)	(358,756)
Net increase in cash, cash equivalents and restricted cash	147,991	(36,824)
Cash, cash equivalents, beginning of period	67,088
Cash and cash equivalents and restricted cash, beginning of period	201,906	329,977
Cash, cash equivalents, end of period	101,565	53,477
Cash and cash equivalents and restricted cash, end of period	$ 349,897	293,153
Impact of ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		13,296
Net cash used in investing activities		112,890
Net cash used in financing activities		(1,493)
Net (decrease) increase in cash, cash equivalents		161,517
Net increase in cash, cash equivalents and restricted cash		(36,824)
Cash, cash equivalents, beginning of period		(214,994)
Cash and cash equivalents and restricted cash, end of period		239,676
Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		562,360
Net cash used in investing activities		(366,614)
Net cash used in financing activities		(357,263)
Net (decrease) increase in cash, cash equivalents		(161,517)
Cash, cash equivalents, beginning of period		214,994
Cash, cash equivalents, end of period		$ 53,477