Quarterly Financial Data - Schedule of Quarterly Financial Information (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2011
Quarterly Financial Data [Line Items]
Income tax out of period adjustments	$ 0.4	$ 1.0	$ 0.8

A credit or adjustment for government or taxing authority authorized decrease in taxes owed as a result of meeting certain tax policy conditions.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Name:	us-gaap_IncomeTaxCreditsAndAdjustments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration