Fair Value Measurements and Derivative Instruments - Additional Information (Detail) (Commodity Contract [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Nov. 30, 2014	Aug. 31, 2014
Commodity Contract [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Pretax losses continued to be deferred in Accumulated other comprehensive income (loss)	$ 0.1	$ 2.1
Deferred gain (loss), net of tax, recorded in other comprehensive income	$ 0.3

Amount before tax, after reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration