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Customer Concentration and Revenue Information - Contract Revenues by Customer Type (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 30, 2021	Oct. 24, 2020	Jul. 25, 2020	Apr. 25, 2020	Jan. 25, 2020	Oct. 26, 2019	Jul. 27, 2019	Apr. 27, 2019	Jan. 30, 2021	Jan. 25, 2020	Jan. 26, 2019
Concentration Risk [Line Items]
Amount	$ 750,665	$ 810,256	$ 823,921	$ 814,322	$ 737,603	$ 884,115	$ 884,221	$ 833,743	$ 3,199,165	$ 3,339,682	$ 3,127,700
% of Total									100.00%	100.00%	100.00%
Revenue Benchmark | Customer Concentration Risk
Concentration Risk [Line Items]
Amount									$ 3,199,200	$ 3,339,700	$ 3,127,700
% of Total									100.00%	100.00%	100.00%
Revenue Benchmark | Customer Concentration Risk | Verizon Communications Inc.
Concentration Risk [Line Items]
Amount									$ 601,600	$ 728,200	$ 599,800
% of Total									18.80%	21.80%	19.20%
Revenue Benchmark | Customer Concentration Risk | Lumen Technologies
Concentration Risk [Line Items]
Amount									$ 542,000	$ 547,800	$ 425,600
% of Total									16.90%	16.40%	13.60%
Revenue Benchmark | Customer Concentration Risk | Comcast Corporation
Concentration Risk [Line Items]
Amount									$ 533,900	$ 503,200	$ 650,200
% of Total									16.70%	15.10%	20.80%
Revenue Benchmark | Customer Concentration Risk | AT&T Inc.
Concentration Risk [Line Items]
Amount									$ 533,700	$ 687,900	$ 664,200
% of Total									16.70%	20.60%	21.20%
Revenue Benchmark | Customer Concentration Risk | Total other customers combined
Concentration Risk [Line Items]
Amount									$ 988,000	$ 872,600	$ 787,900
% of Total									30.90%	26.10%	25.20%

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