Long-Term Debt (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Jun. 30, 2011
Long-Term Debt [Abstract]
Maximum borrowing capacity	$ 160		$ 160
Maximum borrowing capacity on obtaining consent of the issuing bank	260		260
Line of credit facility, expiration date	October 2012
Line of credit facility, amount outstanding	0		0
Standby letters of credit, amount outstanding	6.7
Interest paid	$ 0	$ 0
Maximum leverage ratio	3
Minimum interest coverage ratio	2.5