Long-term Debt (Details) (USD $)	1 Months Ended
	Sep. 30, 2012	Mar. 31, 2013	Jun. 30, 2012
Debt Instrument [Line Items]
Long-term Debt		$ 355,000,000	$ 380,000,000
Current portion of long-term debt		(50,000,000)	(105,000,000)
Long-term debt		305,000,000	275,000,000
Intercompany receivables, interest rate at period end		3.25%
Line of Credit [Member] | Asset Backed Bank Facility [Member]
Debt Instrument [Line Items]
Accounts receivable oustanding under the revolving agreement		152,200,000
Long-term Debt		65,000,000	65,000,000
Line of credit facility, maximum borrowing capacity		100,000,000
Debt term	2 years
Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt		15,000,000	40,000,000
Line of credit facility, maximum borrowing capacity		150,000,000
Debt term	5 years
Senior Notes [Member] | Senior Notes Due 2013 [Member]
Debt Instrument [Line Items]
Long-term Debt		50,000,000	50,000,000
Stated interest rate		6.70%
Senior Notes [Member] | Senior Notes Due 2014 [Member]
Debt Instrument [Line Items]
Long-term Debt		25,000,000	25,000,000
Stated interest rate		7.19%
Senior Notes [Member] | Senior Notes Due 2015 [Member]
Debt Instrument [Line Items]
Long-term Debt		50,000,000	50,000,000
Stated interest rate		2.62%
Senior Notes [Member] | Senior Notes Due 2016 [Member]
Debt Instrument [Line Items]
Long-term Debt		50,000,000	50,000,000
Stated interest rate		3.04%
Senior Notes [Member] | Senior Notes Due 2017 [Member]
Debt Instrument [Line Items]
Long-term Debt		50,000,000	50,000,000
Stated interest rate		3.04%
Senior Notes [Member] | Senior Notes Due 2018 [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 50,000,000	$ 50,000,000
Stated interest rate		3.04%