Long-term Debt - Schedule of Long-term Debt (Details) - USD ($)	Sep. 30, 2020	Jun. 30, 2020
Principal Balance
Principal Balance	$ 3,044,400,000	$ 3,045,400,000
Current portion of long-term debt	(4,100,000)	(4,100,000)
Long-term debt, principal balance	3,040,300,000	3,041,300,000
Unamortized Discount and Debt Issuance Costs
Unamortized Discount and Debt Issuance Costs	(56,800,000)	(59,500,000)
Current portion of long-term debt, unamortized discount and debt issuance costs	0	0
Long-term debt, unamortized discount and debt issuance costs	(56,800,000)	(59,500,000)
Carrying Value
Long-term debt, including current maturities	2,987,600,000	2,985,900,000
Current portion of long-term debt	(4,100,000)	(4,100,000)
Long-term debt, carrying value	2,983,500,000	2,981,800,000
Senior Unsecured Notes | 6.875% senior notes, due February 1, 2026
Principal Balance
Principal Balance	1,272,900,000	1,272,900,000
Unamortized Discount and Debt Issuance Costs
Unamortized Discount and Debt Issuance Costs	(18,000,000.0)	(18,700,000)
Carrying Value
Long-term debt, including current maturities	$ 1,254,900,000	$ 1,254,200,000
Debt instrument, stated interest rate	6.875%	6.875%
Senior Secured Notes | 6.500% senior notes, due July 1, 2025
Principal Balance
Principal Balance	$ 300,000,000.0	$ 300,000,000.0
Unamortized Discount and Debt Issuance Costs
Unamortized Discount and Debt Issuance Costs	(4,800,000)	(5,000,000.0)
Carrying Value
Long-term debt, including current maturities	$ 295,200,000	$ 295,000,000.0
Debt instrument, stated interest rate	6.50%	6.50%
Variable-rate credit facility | Variable-rate credit facility | Senior credit facility term loan, due January 31, 2025
Principal Balance
Principal Balance	$ 1,062,500,000	$ 1,062,500,000
Unamortized Discount and Debt Issuance Costs
Unamortized Discount and Debt Issuance Costs	(12,400,000)	(13,100,000)
Carrying Value
Long-term debt, including current maturities	1,050,100,000	1,049,400,000
Variable-rate credit facility | Variable-rate credit facility | Senior credit facility incremental term loan, due January 31, 2025
Principal Balance
Principal Balance	409,000,000.0	410,000,000.0
Unamortized Discount and Debt Issuance Costs
Unamortized Discount and Debt Issuance Costs	(21,600,000)	(22,700,000)
Carrying Value
Long-term debt, including current maturities	387,400,000	387,300,000
Variable-rate credit facility | Variable-rate credit facility | Revolving credit facility of $350 million, due January 31, 2023
Principal Balance
Principal Balance	0	0
Unamortized Discount and Debt Issuance Costs
Unamortized Discount and Debt Issuance Costs	0	0
Carrying Value
Long-term debt, including current maturities	0	0
Line of credit facility, maximum borrowing capacity	$ 350,000,000	$ 350,000,000