Accounts Receivable, Contract Assets, and Contract Liabilities - Customer Credit Concentration (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 01, 2021	Apr. 25, 2020	Oct. 24, 2020	Jan. 30, 2021
Concentration Risk
Amount	$ 867,545			$ 858,123
% of Total	100.00%	100.00%
Customer Concentration Risk | Trade Accounts Receivable and Costs and Estimated Earnings | Verizon Communications Inc.
Concentration Risk
Amount	$ 361,500			389,900
% of Total	35.10%		37.40%
Customer Concentration Risk | Trade Accounts Receivable and Costs and Estimated Earnings | Lumen Technologies(1)
Concentration Risk
Amount	$ 153,500			173,500
% of Total	14.90%		16.60%
Customer Concentration Risk | Trade Accounts Receivable and Costs and Estimated Earnings | Comcast [Member]
Concentration Risk
Amount	$ 134,800			$ 131,700
% of Total	13.10%		12.60%