Subsequent Events (Details) (Subsequent event, Forecast, USD $)	2 Months Ended
	Sep. 30, 2013 item
Rocky Top
Subsequent events
Number of motor fuel stations to be purchased	30
Number of motor fuel station leases assumed or entered	4
Cash payable	$ 10,600,000
Aggregate purchase price	26,300,000
Period over which purchase consideration will be paid	5 years
Average purchase consideration	5,300,000
Rocky Top | Sellers
Subsequent events
Number of motor fuel stations to be leased	29
Rogers
Subsequent events
Number of motor fuel stations to be purchased	14
Number of motor fuel station leases assumed or entered	3
Aggregate purchase price	$ 21,100,000