Contingent Liabilites and Commitments (Repurchase Commitments Narrative) (Details) (USD $)	9 Months Ended
	May 31, 2014	Aug. 31, 2013
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Repurchase agreement term	18 months
Accrued loss on repurchases	$ 1,420,000	$ 1,287,000
Hypothetical percent change of repurchase assumptions	10.00%
Hypothetical change on repurchase assumptions	366,000
Obligation to Repurchase from Dealers [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Contingent liability on repurchase agreements	361,400,000	232,900,000
State Obligation to Repurchase [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Contingent liability on repurchase agreements	$ 7,000,000	$ 8,000,000