Long-Term Debt (Details) (USD $)	3 Months Ended		9 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012	Jun. 30, 2012
Long-Term Debt [Abstract]
Maximum borrowing capacity	$ 120,000,000		$ 120,000,000		$ 120,000,000
Maximum borrowing capacity on obtaining consent of the issuing bank	200,000,000		200,000,000		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	3,400,000		3,400,000
Interest paid	$ 0	$ 0	$ 0	$ 0
Minimum interest coverage ratio			250.00%
Maximum leverage ratio			300.00%