XML 117 R102.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Concentration of Credit Risk - Revenue Concentration Risk (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jan. 26, 2019 | Oct. 27, 2018 | Jul. 28, 2018 | Apr. 28, 2018 | Jan. 27, 2018 | Oct. 28, 2017 | Jul. 29, 2017 | Apr. 29, 2017 | Jan. 28, 2017 | Oct. 29, 2016 | Jan. 27, 2018 | Jan. 28, 2017 | Jan. 26, 2019 | Jul. 29, 2017 | Jul. 30, 2016
Concentration Risk [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration risk percentage |  |  |  |  |  |  |  |  |  |  | 100.00% |  | 100.00% | 100.00% | 100.00%
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
Sales Revenue, Services, Net | Customer Concentration Risk |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration risk percentage |  |  |  |  |  |  |  |  |  |  |  |  | 10.00% |  |
Sales Revenue, Services, Net | Customer Concentration Risk | AT&T Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration risk percentage |  |  |  |  |  |  |  |  |  |  | 21.60% |  | 20.80% | 17.70% | 13.60%
Revenues |  |  |  |  |  |  |  |  |  |  | $ 304,400 |  | $ 650,200 | $ 543,600 | $ 363,100
Sales Revenue, Services, Net | Customer Concentration Risk | Comcast Corporation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  | $ 113,600 |  |
Sales Revenue, Services, Net | Customer Concentration Risk | Verizon Communications Inc.(1) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration risk percentage |  |  |  |  |  |  |  |  |  |  | 17.50% |  | 13.60% | 18.20% | 14.70%
Revenues |  |  |  |  |  |  |  |  |  |  | $ 247,000 |  | $ 425,600 | $ 556,800 | $ 394,000
Sales Revenue, Services, Net | Customer Concentration Risk | Verizon Communications Inc |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration risk percentage |  |  |  |  |  |  |  |  |  |  | 12.00% |  | 19.20% | 9.20% | 11.20%
Revenues |  |  |  |  |  |  |  |  |  |  | $ 168,700 |  | $ 599,800 | $ 282,700 | $ 298,200
Sales Revenue, Services, Net | Customer Concentration Risk | Other Customers [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration Risk [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Concentration risk percentage |  |  |  |  |  |  |  |  |  |  | 28.30% |  | 25.20% | 28.60% | 36.10%
Revenues |  |  |  |  |  |  |  |  |  |  | $ 401,100 |  | $ 787,900 | $ 877,100 | $ 966,300

X
- 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. + Details
Name: | us-gaap_ConcentrationRiskLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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 -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045 + Details
Name: | us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueServicesNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=dy_ComcastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=dy_WindstreamCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=dy_CenturylinkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=dy_VerizonMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=dy_OtherCustomersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |