Debt (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Jan. 04, 2017	Jun. 22, 2015
Debt Instrument [Line Items]
Amortization of Financing Costs		$ 2,382	$ 2,513	$ 7,278	$ 3,864
Repayments of Long-term Debt	$ 200,000			175,000	57,500
Proceeds from issuance of long-term debt				0	$ 3,500,000
Credit Agreement [Member]
Debt Instrument [Line Items]
Payments of Financing Costs				45,492
Senior Secured Term Loan [Member] | Credit Agreement [Member]
Debt Instrument [Line Items]
Debt instrument, principal amount							$ 3,500,000
Debt Instrument, quarterly payment as a percent of total borrowings							1.25%
Outstanding debt		3,281,250		3,281,250		$ 3,081,250
Line of Credit [Member] | Credit Agreement [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity							$ 500,000
Letters of credit, amount outstanding		14,632		14,632
Line of credit facility, borrowing availability		$ 485,368		$ 485,368
Letter of Credit [Member] | Credit Agreement [Member]
Debt Instrument [Line Items]
Sublimit for letter of credit for working capital requirements and other general corporate purposes							100,000
Bridge Loan [Member] | Credit Agreement [Member]
Debt Instrument [Line Items]
Sublimit for letter of credit for working capital requirements and other general corporate purposes							$ 25,000