Organization, Basis of Presentation and Significant Accounting Policies (Details 4) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	$ 981,359	$ 933,778
Net cash used in investing activities	(495,456)	(624,752)
Net cash used in financing activities	(406,218)	(421,892)
Net increase in cash, cash equivalents and restricted cash	79,685	(112,866)
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	55,887	36,042
Cash and cash equivalents and restricted cash, end of period	$ 281,591	217,111
Impact of ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		16,205
Net cash used in investing activities		51,479
Net cash used in financing activities		(1,598)
Net (decrease) increase in cash, cash equivalents		178,952
Net increase in cash, cash equivalents and restricted cash		(112,866)
Cash, cash equivalents, beginning of period		(214,994)
Cash and cash equivalents and restricted cash, end of period		181,069
Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		917,573
Net cash used in investing activities		(676,231)
Net cash used in financing activities		(420,294)
Net (decrease) increase in cash, cash equivalents		(178,952)
Cash, cash equivalents, beginning of period		214,994
Cash, cash equivalents, end of period		$ 36,042