Warranty (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jul. 31, 2012
Retrofit Emissions Products [Member]
Product Warranty [Line Items]
Expense incurred on increased warranty accruals	$ 3.6
Off-Road Products [Member]
Product Warranty [Line Items]
Expense incurred on increased warranty accruals	1.8
On-Road Products [Member]
Product Warranty [Line Items]
Expense incurred on increased warranty accruals	$ 4.1

The expense charged against earnings for the period pertaining to standard and extended warranties on the entity's goods and services granted to customers.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(3,4))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

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