XML 94 R82.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Concentration of Credit Risk - Customer Type (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Apr. 28, 2018 | Apr. 29, 2017
Concentration Risk |  |
Contract revenues | $ 731,375 | $ 786,338
Concentration risk percentage | 100.00% | 100.00%
Customer Concentration Risk | Sales Revenue, Services, Net |  |
Concentration Risk |  |
Concentration risk percentage | 10.00% |
Customer Concentration Risk | Sales Revenue, Services, Net | Telecommunications |  |
Concentration Risk |  |
Contract revenues | $ 667,200 | $ 725,300
Concentration risk percentage | 91.20% | 92.20%
Customer Concentration Risk | Sales Revenue, Services, Net | Underground facility locating |  |
Concentration Risk |  |
Contract revenues | $ 45,100 | $ 42,100
Concentration risk percentage | 6.20% | 5.40%
Customer Concentration Risk | Sales Revenue, Services, Net | Electrical and gas utilities and other |  |
Concentration Risk |  |
Contract revenues | $ 19,100 | $ 18,900
Concentration risk percentage | 2.60% | 2.40%

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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(d)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_SalesRevenueServicesNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

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

X
- Details
Name: | dy_CustomerTypeAxis=dy_TelecommunicationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dy_CustomerTypeAxis=dy_UndergroundFacilityLocatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dy_CustomerTypeAxis=dy_ElectricalandGasUtilitiesandOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |