Income Taxes - Income Taxes Paid - Narrative (Detail) - USD ($) $ in Millions	12 Months Ended
Apr. 29, 2018	Apr. 30, 2017	May 01, 2016
Income Tax Disclosure [Abstract]
Income tax payments, net of income tax refunds	$ 4.0	$ 5.5	$ 6.7

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

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