Accounts Receivable Concentration Risk (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 28, 2018	Jul. 29, 2017	Jul. 28, 2018	Jan. 27, 2018	Jul. 29, 2017	Jan. 28, 2018
Concentration Risk
Accounts receivable, net	$ 684,862		$ 684,862	$ 318,684		$ 630,400
Concentration risk percentage	100.00%	100.00%	100.00%		100.00%
Customer Concentration Risk | Trade Accounts Receivable and Costs and Estimated Earnings | Comcast Corporation
Concentration Risk
Accounts receivable, net	$ 160,800		$ 160,800	$ 166,500
Concentration risk percentage			19.00%	24.50%
Customer Concentration Risk | Trade Accounts Receivable and Costs and Estimated Earnings | Verizon Communications Inc.
Concentration Risk
Accounts receivable, net	241,300		$ 241,300	$ 98,200
Concentration risk percentage			28.50%	14.40%
Customer Concentration Risk | Trade Accounts Receivable and Costs and Estimated Earnings | CenturyLink, Inc.
Concentration Risk
Accounts receivable, net	126,500		$ 126,500	$ 126,000
Concentration risk percentage			15.00%	18.50%
Customer Concentration Risk | Trade Accounts Receivable and Costs and Estimated Earnings | AT&T Inc.
Concentration Risk
Accounts receivable, net	$ 98,100		$ 98,100	$ 79,200
Concentration risk percentage			11.60%	11.60%