Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Senior notes	$ 4,500,000	$ 4,500,000
Acquisition obligations and other notes payable	150,512	117,547
Capital lease obligations	297,170	292,252
Total debt principal outstanding	9,400,182	9,184,799
Discount and deferred financing costs	(63,951)	(79,861)
Carrying amount of long-term debt, net of unamortized discounts	9,336,231	9,104,938
Less current portion	(178,213)	(160,262)
Long-term debt	9,158,018	8,944,676
Term Loan A
Debt Instrument [Line Items]
Senior secured credit facilities	775,000	862,500
Term Loan B
Debt Instrument [Line Items]
Senior secured credit facilities	3,377,500	3,412,500
Revolver
Debt Instrument [Line Items]
Senior secured credit facilities	$ 300,000	$ 0