Notes Payable and Indebtedness - Summary (Details) $ in Millions	6 Months Ended
Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Feb. 08, 2019
Debt Maturing Within One Year:
Principal amount, current maturities of long-term debt	$ 325.3
Principal Amount		$ 82.0
Debt Issuance Costs and Discount*	0.0	0.1
Carrying value, current maturities of long-term debt	325.3
Carrying Value	325.3	81.9
Debt Maturing After One Year:
Principal Amount	3,735.9	3,961.0
Debt Issuance Costs and Discount*	115.1	142.1
Carrying Value	3,620.8	3,818.9
Total debt
Principal amount, long-term debt	4,061.2
Principal amount, long-term and short-term debt		4,043.0
Debt Issuance Costs and Discount	115.1	142.2
Carrying Value	3,946.1
Carrying Value		3,900.8
New Senior Unsecured Notes \| Unsecured Debt - Current
Debt Maturing Within One Year:
Principal amount, current maturities of long-term debt	300.0	0.0
Debt Issuance Costs and Discount*	0.0	0.0
Carrying value, current maturities of long-term debt	300.0	0.0
New Senior Unsecured Notes \| Unsecured Debt Excluding Current Maturities
Debt Maturing After One Year:
Principal Amount	450.0	750.0
Debt Issuance Costs and Discount*	15.7	28.0
Carrying Value	434.3	722.0
New Senior Unsecured Notes \| Unsecured Debt
Total debt
Interest rate on debt instrument (as a percent)			10.25%
Bridge Facility \| Bridge Loan
Debt Maturing Within One Year:
Principal amount, short-term debt		63.0
Debt Issuance Costs and Discount*		0.1
Carrying value, short-term debt		62.9
New Term Loan Facility \| Line of Credit
Debt Maturing After One Year:
Principal Amount	2,498.4	2,511.0
Debt Issuance Costs and Discount*	84.6	98.3
Carrying Value	2,413.8	2,412.7
New Term Loan Facility \| Line of Credit \| Secured Debt
Debt Maturing Within One Year:
Principal amount, current maturities of long-term debt	25.3	19.0
Debt Issuance Costs and Discount*	0.0	0.0
Carrying value, current maturities of long-term debt	25.3	19.0
New Revolving Facility \| Line of Credit \| Revolving Credit Facility
Debt Maturing After One Year:
Principal Amount	87.5	0.0
Debt Issuance Costs and Discount*	0.0	0.0
Carrying Value	$ 87.5	0.0
Total debt
Maximum ratio of first lien net indebtedness to consolidated EBITDA	6.75
Applicable threshold for maximum ratio of first lien net indebtedness to consolidated EBITDA (as a percent)	35.00%
New Senior Secured Notes \| Secured Debt
Debt Maturing After One Year:
Principal Amount	$ 700.0	700.0
Debt Issuance Costs and Discount*	14.8	15.8
Carrying Value	$ 685.2	$ 684.2
Total debt
Interest rate on debt instrument (as a percent)			6.875%

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