Segment Information - Geographic Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 27, 2019	Apr. 28, 2018	Apr. 29, 2017
Geographic Information
Long-lived assets	$ 417,421	$ 275,449	$ 262,989
Geographic concentration | Sales
Geographic Information
Percentage of sales	100.00%	100.00%	100.00%
Domestic/United States
Geographic Information
Long-lived assets	$ 389,892	$ 251,778	$ 239,198
Domestic/United States | Geographic concentration | Sales
Geographic Information
Percentage of sales	89.00%	87.00%	88.00%
International
Geographic Information
Long-lived assets	$ 27,529	$ 23,671	$ 23,791
Canada | Geographic concentration | Sales
Geographic Information
Percentage of sales	6.00%	7.00%	7.00%
Other | Geographic concentration | Sales
Geographic Information
Percentage of sales	5.00%	6.00%	5.00%