Organization, Basis of Presentation and Significant Accounting Policies - Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Aug. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Capitalized Maintenance Expense, Deferred During the Period	$ 0.3	$ 18.9
Minimum [Member] | Major Maintenance Activities Requiring Shutdown [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years
Maximum [Member] | Major Maintenance Activities Requiring Shutdown [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	4 years
Other Assets [Member] | Accounting Standards Update 2015-03 [Member]
Finite-Lived Intangible Assets [Line Items]
Debt Issuance Costs, Net			$ (5.6)
Long-term Debt [Member] | Accounting Standards Update 2015-03 [Member]
Finite-Lived Intangible Assets [Line Items]
Debt Issuance Costs, Net			$ 5.6