Other Compensation Plans Narrative (Details) $ in Thousands	12 Months Ended
	Apr. 28, 2017 USD ($) hour plan shares	Apr. 29, 2016 USD ($)	Apr. 24, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Minimum hours of service required for 401(k) eligibility (at least) | hour	1,000
Employer match contribution	$ 1,426	$ 988	$ 946
Number of nonqualified deferred compensation plans | plan	3
Deferred compensation obligation, shares | shares	20,949
Rabbi trust assets	$ 22,353	20,662
BEEDP and BEDDP Plans
Defined Benefit Plan Disclosure [Line Items]
Share based obligations	1,398	673
Expenses related to investments of employee deferrals	1,031	1,162	$ 1,236
Prepaid Expenses and Other Current Assets
Defined Benefit Plan Disclosure [Line Items]
Short-term securities held in Rabbi Trust	$ 984	$ 3,290