Supplementary Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Jan. 26, 2019	Jan. 27, 2018	Jul. 29, 2017	Jan. 26, 2019	Jan. 27, 2018
Deferred Compensation Arrangement with Individual, Compensation Expense					$ 5,361
Restructuring and other charges	$ 2,500	$ 0		$ 2,500	5,429
Patrick Maloney [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense	1,843
Max Roberts [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense			$ 4,424
Patrick Maloney [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 657
Michael Huseby [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense					250
Max Roberts [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense					$ 562