Basis of Presentation - Early Adoption of New Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in operating expenses	$ (339,289)	$ (317,242)	$ (675,248)	$ (625,578)
Total non-operating (expense) income	(76,897)	(65,701)	(135,855)	(123,563)
Effect of Accounting Change | Accounting Standards Update 2017-06
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in operating expenses	1,900	2,600	3,300	4,000
Total non-operating (expense) income	$ (1,900)	$ (2,600)	$ (3,300)	$ (4,000)