Customer Concentration and Revenue Information - Customer Type (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jul. 26, 2025	Jul. 27, 2024	Jul. 26, 2025	Jul. 27, 2024
Concentration Risk
Contract revenues	$ 1,377,944	$ 1,203,059	$ 2,636,551	$ 2,345,482
Customer Concentration Risk \| Revenue Benchmark
Concentration Risk
Contract revenues	$ 1,377,900	$ 1,203,100	$ 2,636,600	$ 2,345,500
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
% of Total	100.00%	100.00%	100.00%	100.00%
Customer Concentration Risk \| Revenue Benchmark \| Telecommunications
Concentration Risk
Contract revenues	$ 1,269,100	$ 1,086,200	$ 2,418,000	$ 2,113,000
Concentration risk, percentage	92.10%	90.30%	91.70%	90.00%
Customer Concentration Risk \| Revenue Benchmark \| Underground facility locating
Concentration Risk
Contract revenues	$ 84,100	$ 82,100	$ 166,400	$ 163,100
Concentration risk, percentage	6.10%	6.80%	6.30%	7.00%
Customer Concentration Risk \| Revenue Benchmark \| Electrical and gas utilities and other
Concentration Risk
Contract revenues	$ 24,700	$ 34,800	$ 52,200	$ 69,400
Concentration risk, percentage	1.80%	2.90%	2.00%	3.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References + Details

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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