Long-Term Debt (Details) $ in Thousands		12 Months Ended
	Dec. 15, 2016 USD ($)	Aug. 31, 2017 USD ($)	Aug. 31, 2016 USD ($)	Aug. 31, 2015 USD ($)
Long-term debt
Outstanding balance			$ 43,400
Principal payment		$ 43,400	8,400	$ 9,000
New Credit Agreement
Long-term debt
Maximum borrowing capacity	$ 150,000	150,000
Additional borrowing capacity	$ 50,000
Net leverage ratio	3.25
Consolidated fixed charge coverage ratio	1.25
Carrying value of direct and indirect domestic subsidiaries		$ 162,818
Term of debt	5 years
Term of potential debt		7 years
New Credit Agreement | London Interbank Offered Rate (LIBOR)
Long-term debt
Interest payment due	3 months
New Credit Agreement | London Interbank Offered Rate (LIBOR) | Minimum
Long-term debt
Interest rate margin on variable rate basis (as a percent)	1.00%
New Credit Agreement | London Interbank Offered Rate (LIBOR) | Maximum
Long-term debt
Interest rate margin on variable rate basis (as a percent)	1.75%
Term note payable through June 27, 2017
Long-term debt
Outstanding balance			$ 43,400
Term note payable through June 27, 2017 | London Interbank Offered Rate (LIBOR)
Long-term debt
Effective interest rate (as a percent)			2.27%
Term note payable through June 27, 2017 | London Interbank Offered Rate (LIBOR) | Minimum
Long-term debt
Interest rate margin on variable rate basis (as a percent)	1.75%
Term note payable through June 27, 2017 | London Interbank Offered Rate (LIBOR) | Maximum
Long-term debt
Interest rate margin on variable rate basis (as a percent)	2.25%
Term note payable through June 27, 2017 | Through June 2014
Long-term debt
Principal payment	$ 1,400
Term note payable through June 27, 2017 | After June 2014 through June 2015
Long-term debt
Principal payment	1,750
Term note payable through June 27, 2017 | After June 2015 through March 2017
Long-term debt
Principal payment	$ 2,100