Long-term Debt (Schedule of Long-term Debt and Maturities of Long-term Debt) (Details) (USD $)	Jun. 30, 2014	Jun. 30, 2013
Long-term Debt [Abstract]
Total long-term debt	$ 715,000,000	$ 350,000,000
Current portion of long-term debt	(87,500,000)	(50,000,000)
Long-term debt	627,500,000	300,000,000
Principal payments on debt due in succeeding fiscal years [Abstract]
2015	87,500,000
2016	62,500,000
2017	75,000,000
2018	75,000,000
2019	265,000,000
Thereafter	150,000,000
Total long-term debt	715,000,000	350,000,000
Variable-rate Credit Facilities [Member] | Asset-backed Bank Facility [Member]
Long-term Debt [Abstract]
Maximum borrowing capacity	100,000,000
Total long-term debt	70,000,000	75,000,000
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	70,000,000	75,000,000
Variable-rate Credit Facilities [Member] | Revolving Credit Facility [Member]
Long-term Debt [Abstract]
Maximum borrowing capacity	200,000,000
Total long-term debt	20,000,000	0
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	20,000,000	0
Notes Payable to Banks [Member] | Term Loan Facility [Member]
Long-term Debt [Abstract]
Maximum borrowing capacity	250,000,000
Total long-term debt	250,000,000	0
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	250,000,000	0
Private Placement Notes [Member] | Senior Notes 6.70% Due 7/13/2013 [Member]
Long-term Debt [Abstract]
Stated interest rate	6.70%
Total long-term debt	0	50,000,000
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	0	50,000,000
Private Placement Notes [Member] | Senior Notes 7.19% Due 7/13/2014 [Member]
Long-term Debt [Abstract]
Stated interest rate	7.19%
Total long-term debt	25,000,000	25,000,000
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	25,000,000	25,000,000
Private Placement Notes [Member] | Senior Notes 2.62% Due 3/1/2015 [Member]
Long-term Debt [Abstract]
Stated interest rate	2.62%
Total long-term debt	50,000,000	50,000,000
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	50,000,000	50,000,000
Private Placement Notes [Member] | Senior Notes 3.04% Due 3/1/2016 [Member]
Long-term Debt [Abstract]
Stated interest rate	3.04%
Total long-term debt	50,000,000	50,000,000
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	50,000,000	50,000,000
Private Placement Notes [Member] | Senior Notes 3.04% Due 3/1/2017 [Member]
Long-term Debt [Abstract]
Stated interest rate	3.04%
Total long-term debt	50,000,000	50,000,000
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	50,000,000	50,000,000
Private Placement Notes [Member] | Senior Notes 3.04% Due 3/1/2018 [Member]
Long-term Debt [Abstract]
Stated interest rate	3.04%
Total long-term debt	50,000,000	50,000,000
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	50,000,000	50,000,000
Private Placement Notes [Member] | Senior Notes Due 2024 [Member]
Long-term Debt [Abstract]
Total long-term debt	150,000,000	0
Principal payments on debt due in succeeding fiscal years [Abstract]
Total long-term debt	$ 150,000,000	$ 0