Long-Term Debt (Details) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Jun. 30, 2011	Mar. 31, 2012 New Credit Agreement [Member]	Apr. 18, 2012 New Credit Agreement [Member]
Maximum borrowing capacity	$ 160,000,000		$ 160,000,000		$ 160,000,000		$ 120,000,000
Maximum borrowing capacity on obtaining consent of the issuing bank	260,000,000		260,000,000		260,000,000		200,000,000
Line of credit facility, expiration date						Apr. 18, 2017
Line of credit facility, amount outstanding	0		0		0
Standby letters of credit, amount outstanding	6,700,000		6,700,000
Interest paid	$ 0	$ 0	$ 0	$ 0
Minimum interest coverage ratio			2.5
Maximum leverage ratio			3