Warranties (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended
Jul. 27, 2012	Jan. 27, 2012
Product Warranties Disclosures [Abstract]
Change in liability for pre-existing warranties related to LeTourneau	$ 6.1	$ 10.0

Total liability for standard and extended product warranties acquired in a business acquisition.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (c)

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

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