Long-Term Indebtedness (Details) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2014	Aug. 31, 2013
Debt Instrument [Line Items]
Total Senior Indebtedness	$ 390,000	$ 515,000
Less: current maturities of long-term debt	(2,250)	0
Total long-term debt, less current maturities	387,750	515,000
Line of Credit
Debt Instrument [Line Items]
Total Senior Indebtedness	90,000	215,000
Line of Credit | Senior Credit Facility - Revolver
Debt Instrument [Line Items]
Total Senior Indebtedness	0	125,000
Line of Credit | Senior Credit Facility - Term Loan
Debt Instrument [Line Items]
Total Senior Indebtedness	90,000	90,000
Senior Notes | 5.625% Senior Notes
Debt Instrument [Line Items]
Total Senior Indebtedness	$ 300,000	$ 300,000