Debt (Details) (USD $)	12 Months Ended	0 Months Ended	12 Months Ended			0 Months Ended	1 Months Ended
	Sep. 30, 2013	Apr. 30, 2010 Senior Credit Facility, expiring April 30, 2013	Sep. 30, 2013 Amended Senior Credit Facility, expiring May 31, 2014	Mar. 13, 2012 Amended Senior Credit Facility, expiring May 31, 2014	Sep. 30, 2013 Amended Senior Credit Facility, expiring May 31, 2014 Issued letters of credit	Oct. 02, 2011 Subordinated Note Jacobs Trading	Nov. 30, 2012 Subordinated Note Jacobs Trading
Debt
Term		3 years
Maximum borrowings		$ 30,000,000		$ 75,000,000
Interest rate basis			30 day LIBOR
Percentage added to reference rate			1.25%
Interest rate at period end (as a percent)			1.431%
Amount outstanding			0		7,200,000
Available borrowing capacity			67,800,000
Principal amount of debt issued						40,000,000
Interest rate (as a percent)						5.00%
Gain on the early extinguishment of debt	$ 1,000,000						$ 1,000,000