Debt - Interest Rate Swaps (Details)		9 Months Ended
	Jun. 30, 2020 USD ($)	Sep. 30, 2020 USD ($) outstanding_contract derivative_instrument	Sep. 30, 2019 USD ($)	Jun. 22, 2020 USD ($)	Dec. 31, 2019 USD ($) outstanding_contract
Derivative [Line Items]
Number of contracts | outstanding_contract		42			180
Interest rate swap contracts total notional value		$ 1,611,495,000			$ 2,004,858,000
Repayments of long-term debt		2,053,342,000	$ 74,612,000
Variable rate debt		200,000,000.0
Senior Notes Due 2028 | Senior Notes
Derivative [Line Items]
Aggregate principal amount		$ 800,000,000.0		$ 800,000,000
Term loans | 2016 Agreement | Bank Term Loan - A Facility
Derivative [Line Items]
Repayments of long-term debt	$ 787,900,000
Interest rate swaps
Derivative [Line Items]
Number of contracts | derivative_instrument		4
Interest rate swap contracts total notional value		$ 1,400,000,000
Term of contract		30 days
Loss on release of interest rate swap recognized in AOCI		$ 111,200,000
Net negative fair value (liability)		(120,500,000)			(64,800,000)
Interest rate swaps | Accumulated Other Comprehensive Loss, Net
Derivative [Line Items]
Net negative fair value (liability)		(84,600,000)			$ (47,200,000)
Interest rate swaps | Other Expense
Derivative [Line Items]
Loss on release of interest rate swap recognized in earnings		$ 10,300,000
Interest rate swaps | Minimum
Derivative [Line Items]
Fixed interest rate		2.13%
Interest rate swaps | Maximum
Derivative [Line Items]
Fixed interest rate		3.04%