Long-term Debt (Schedule of Long-term Debt) (Details) - USD ($)	Jun. 30, 2019	Jun. 30, 2018	Jan. 31, 2018
Debt Instrument [Line Items]
Principal Balance	$ 2,370,400,000	$ 3,195,500,000
Unamortized Discount and Debt Issuance Costs	(37,100,000)	(59,900,000)
Carrying Value	2,333,300,000	3,135,600,000
Current portion of long-term debt	0	(18,000,000.0)
Current portion of long-term debt, unamortized discount and debt issuance costs	0	300,000
Current portion of long-term debt	0	(17,700,000)
Long-term debt, principal balance	2,370,400,000	3,177,500,000
Long-term debt, unamortized discount and debt issuance costs	(37,100,000)	(59,600,000)
Long-term debt, carrying value	$ 2,333,300,000	$ 3,117,900,000
Senior Unsecured Notes | 6.875% senior notes, due 2/1/2026
Debt Instrument [Line Items]
Stated interest rate	6.875%	6.875%	6.875%
Principal Balance	$ 1,272,900,000	$ 1,400,000,000.0
Unamortized Discount and Debt Issuance Costs	(21,500,000)	(26,500,000)
Carrying Value	1,251,400,000	1,373,500,000
Variable-rate credit facility | Variable-rate credit facility | Senior credit facility term loan, due 1/31/2025
Debt Instrument [Line Items]
Principal Balance	1,062,500,000	1,795,500,000
Unamortized Discount and Debt Issuance Costs	(15,600,000)	(33,400,000)
Carrying Value	1,046,900,000	1,762,100,000
Variable-rate credit facility | Variable-rate credit facility | Revolving credit facility of $350 million, due 1/31/2023
Debt Instrument [Line Items]
Maximum borrowing capacity	350,000,000
Principal Balance	35,000,000.0	0
Unamortized Discount and Debt Issuance Costs	0	0
Carrying Value	$ 35,000,000.0	$ 0