Segment Information - Geographic Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2016	Apr. 25, 2015	Apr. 26, 2014
Geographic Information
Long-lived assets	$ 218,464	$ 195,583	$ 154,343
Geographic concentration | Sales
Geographic Information
Percentage of sales	100.00%	100.00%	100.00%
Domestic/United States
Geographic Information
Long-lived assets	$ 211,021	$ 187,224	$ 147,538
Domestic/United States | Geographic concentration | Sales
Geographic Information
Percentage of sales	89.00%	87.00%	86.00%
International
Geographic Information
Long-lived assets	$ 7,443	$ 8,359	$ 6,805
Canada | Geographic concentration | Sales
Geographic Information
Percentage of sales	7.00%	7.00%	8.00%
Other | Geographic concentration | Sales
Geographic Information
Percentage of sales	4.00%	6.00%	6.00%