Basis of Presentation and Summary of Significant Accounting Policies (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash flows from operating activities	$ 81,323	$ 73,604
Net cash flows from investing activities	$ (171,628)	(87,683)
As Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash flows from operating activities		68,516
Net cash flows from investing activities		(86,238)
Accounting Standards Update 2016-18 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash flows from operating activities		5,088
Net cash flows from investing activities		$ (1,445)