Customer Concentration and Revenue Information - Revenue Concentration Risk (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
Revenue Benchmark \| Customer Concentration Risk
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%
Revenue Benchmark \| Customer Concentration Risk \| AT&T Inc.
Concentration Risk
Contract revenues	$ 373,000	$ 210,200	$ 698,100	$ 425,700
Concentration risk, percentage	27.10%	17.50%	26.50%	18.20%
Revenue Benchmark \| Customer Concentration Risk \| Lumen Technologies
Concentration Risk
Contract revenues	$ 155,400	$ 163,700	$ 280,600	$ 320,500
Concentration risk, percentage	11.30%	13.60%	10.60%	13.70%
Revenue Benchmark \| Customer Concentration Risk \| Total other customers combined
Concentration Risk
Contract revenues	$ 849,500	$ 829,200	$ 1,657,900	$ 1,599,300
Concentration risk, percentage	61.60%	68.90%	62.90%	68.10%

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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DYCOM INDUSTRIES INC 10-Q