Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Income Tax Contingency [Line Items]
Additional income tax provision		$ 1,559,000
State net operating loss carryforwards, valuation allowance	8,700,000	7,400,000
Unrecognized tax benefits	2,583,000	5,451,000	4,775,000
Unrecognized tax benefits, accrued interest and penalty	300,000	700,000
Decrease in unrecognized tax benefits	2,900,000
Decrease in unrecognized tax benefits impacting tax rate	700,000
Unrecognized tax benefits, income tax penalties and interest net benefit	400,000	100,000	500,000
Unrecognized tax benefits favorably impact the effective tax rate	2,600,000	1,900,000	3,100,000
Possible change in unrecognized tax benefits, lower bound	1,300,000
Possible change in unrecognized tax benefits, upper bound	(2,000,000)
Income taxes receivable	9,800,000
Income taxes receivable, noncurrent		10,300,000
Income taxes receivable, current	$ 7,728,000
Minimum [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Dates	Dec. 01, 2013
Maximum [Member]
Income Tax Contingency [Line Items]
Operating Loss Carryforwards, Expiration Dates	May 31, 2034