Customer Concentration and Revenue Information - Customer Type (Details) - USD ($) $ in Thousands	3 Months Ended
	May 01, 2021	Apr. 25, 2020
Concentration Risk
Contract revenues	$ 727,497	$ 814,322
% of Total	100.00%	100.00%
Customer Concentration Risk | Revenue Benchmark
Concentration Risk
% of Total	10.00%
Customer Concentration Risk | Revenue Benchmark | Telecommunications
Concentration Risk
Contract revenues	$ 639,700	$ 726,000
% of Total	87.90%	89.20%
Customer Concentration Risk | Revenue Benchmark | Underground facility locating
Concentration Risk
Contract revenues	$ 65,000	$ 53,300
% of Total	8.90%	6.50%
Customer Concentration Risk | Revenue Benchmark | Electrical and gas utilities and other
Concentration Risk
Contract revenues	$ 22,800	$ 35,000
% of Total	3.20%	4.30%
Five Unnamed Customers | Customer Concentration Risk | Revenue Benchmark
Concentration Risk
% of Total	68.20%	78.50%