Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 28, 2018	Apr. 29, 2017	Jan. 27, 2018
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 5,700	$ 6,200
Intangible Assets, Gross (Excluding Goodwill)	327,517		$ 315,217
Accumulated Amortization	149,442		143,748
Intangible Assets, Net	178,075		171,469
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	11 years 8 months 6 days
Intangible Assets, Gross (Excluding Goodwill)	$ 312,017		299,717
Accumulated Amortization	141,096		135,544
Intangible Assets, Net	$ 170,921		164,173
Trade names
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Usesul life	8 years 3 months 24 days
Intangible Assets, Gross (Excluding Goodwill)	$ 10,350		10,350
Accumulated Amortization	7,992		7,872
Intangible Assets, Net	$ 2,358		2,478
Non-compete agreements
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Usesul life	2 years 2 months 12 days
Intangible Assets, Gross (Excluding Goodwill)	$ 450		450
Accumulated Amortization	354		332
Intangible Assets, Net	$ 96		$ 118

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

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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/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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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

No definition available.

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- Definition

Amount before accumulated amortization of intangible assets, excluding goodwill.

+ References

No definition available.

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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