The number of customers classified as highly concentrated in comparison to total revenue.

No definition available.

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- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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- Definition

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.

+ References

No definition available.

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- 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 275
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- 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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
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Concentration of Credit Risk - Narratives (Details) $ in Thousands	3 Months Ended										6 Months Ended		12 Months Ended
	Jan. 26, 2019 USD ($) customer	Oct. 27, 2018 USD ($)	Jul. 28, 2018 USD ($)	Apr. 28, 2018 USD ($)	Jan. 27, 2018 USD ($)	Oct. 28, 2017 USD ($)	Jul. 29, 2017 USD ($)	Apr. 29, 2017 USD ($)	Jan. 28, 2017 USD ($)	Oct. 29, 2016 USD ($)	Jan. 27, 2018 USD ($)	Jan. 28, 2017 USD ($)	Jan. 26, 2019 USD ($) customer	Jul. 29, 2017 USD ($)	Jul. 30, 2016 USD ($)	Jan. 28, 2018 USD ($)
Concentration Risk [Line Items]
Revenues	$ 748,619	$ 848,237	$ 799,470	$ 731,375	$ 655,133	$ 756,215	$ 780,188	$ 786,338	$ 701,131	$ 799,223	$ 1,411,348	$ 1,500,355	$ 3,127,700	$ 3,066,880	$ 2,672,542
Number of customers classified as highly concentrated \| customer	5												5
Concentration risk percentage											100.00%		100.00%	100.00%	100.00%
Accounts receivable, net	$ 625,258				318,684						$ 318,684		$ 625,258			$ 630,400
Sales Revenue, Services, Net \| Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage													10.00%
Sales Revenue, Services, Net \| Customer Concentration Risk \| ATT [Member]
Concentration Risk [Line Items]
Revenues											$ 290,100		$ 664,200	$ 806,700	$ 650,900
Concentration risk percentage											20.60%		21.20%	26.30%	24.40%
Sales Revenue, Services, Net \| Customer Concentration Risk \| Five Unnamed Customers
Concentration Risk [Line Items]
Concentration risk percentage											75.80%		78.40%	76.80%	70.10%
Trade Accounts Receivable and Costs and Estimated Earnings [Member] \| Customer Concentration Risk \| ATT [Member]
Concentration Risk [Line Items]
Concentration risk percentage											11.60%		11.00%
Accounts receivable, net	$ 90,600				$ 79,200						$ 79,200		$ 90,600