Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 25, 2020	Apr. 27, 2019	Jan. 25, 2020
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 5,200	$ 5,300
Intangible Assets, Gross (Excluding Goodwill)	327,267		$ 327,267
Accumulated Amortization	192,565		187,322
Intangible Assets, Net	134,702		139,945
UtiliQuest
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	4,700		4,700
Accumulated Amortization	0		0
Intangible Assets, Net	$ 4,700		4,700
Customer relationships
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Usesul life	10 years 4 months 24 days
Intangible Assets, Gross (Excluding Goodwill)	$ 312,017		312,017
Accumulated Amortization	183,540		178,411
Intangible Assets, Net	$ 128,477		133,606
Trade names
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Usesul life	7 years 10 months 24 days
Intangible Assets, Gross (Excluding Goodwill)	$ 10,350		10,350
Accumulated Amortization	8,837		8,732
Intangible Assets, Net	$ 1,513		1,618
Non-compete agreements
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Usesul life	9 months 18 days
Intangible Assets, Gross (Excluding Goodwill)	$ 200		200
Accumulated Amortization	188		179
Intangible Assets, Net	$ 12		$ 21

Finite-Lived and Indefinite-Lived Intangible Assets

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- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Remaining amortization period of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Amount before accumulated amortization of intangible assets, excluding goodwill.

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- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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