Significant Accounting Policies - Narrative - Financial Reporting Periods (Details)	12 Months Ended
	Apr. 29, 2017	Apr. 30, 2016	May 02, 2015
Financial Reporting Periods [Line Items]
Fiscal year duration	fifty-two weeks	fifty-two weeks	fifty-two weeks
Minimum
Financial Reporting Periods [Line Items]
Fiscal year duration	fifty-two weeks
Maximum
Financial Reporting Periods [Line Items]
Fiscal year duration	fifty-three weeks