Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	May. 31, 2015	Feb. 28, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014	Aug. 31, 2014
Goodwill [Line Items]
Impairment charge	$ 0	$ 84,353	$ 0	$ 84,353	$ 0
Goodwill Impairment charge		77,992		78,530
Goodwill	612,232			612,232		$ 742,770
Future Amortization Expense, Remainder of 2015	5,900			5,900
Future Amortization Expense, 2016	23,600			23,600
Future Amortization Expense, 2017	22,700			22,700
Future Amortization Expense, 2018	22,300			22,300
Future Amortization Expense, 2019	22,100			22,100
Future Amortization Expense, 2020	21,500			21,500
Future Amortization Expense, Thereafter	86,000			86,000
Energy
Goodwill [Line Items]
Goodwill Impairment charge				78,530
Goodwill	$ 240,715			$ 240,715		$ 350,628
Tradenames
Goodwill [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)		$ 6,362