Retirement Plans and Postretirement Health Care and Life Insurance Benefits - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
Jul. 31, 2013	Oct. 31, 2013 Subsequent Event [Member]
Defined Benefit Plan Disclosure [Line Items]
Company's pension contributions	$ 10.1
Company's estimated pension contributions		$ 13.1

Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

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