Pre-production Costs Related to Long-Term Supply Arrangements - Narrative (Details) - USD ($) $ in Millions	Apr. 29, 2017	Apr. 30, 2016
Preproduction Costs Related to Long-term Supply Arrangements [Abstract]
Pre-production tooling costs	$ 15.5	$ 9.5
Company owned pre-production tooling capitalized within property, plant and equipment	$ 7.1	$ 8.0

The carrying amount as of the balance sheet date of capitalized preproduction costs incurred on long-term supply arrangements, including recoverable costs to design and develop products.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6387057&loc=d3e6169-108318

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 10
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6387057&loc=d3e6233-108318

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 10
-Section S99
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=27011391&loc=d3e105117-122735

Name:	us-gaap_PreproductionCostsRelatedToLongTermSupplyArrangementsCostsCapitalized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant