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Acquisitions (Details) (USD $)
3 Months Ended
Oct. 25, 2014
Jan. 24, 2015
business
Apr. 26, 2014
Jul. 26, 2014
Apr. 25, 2015
Business Acquisition [Line Items]          
Goodwill       $ 269,088,000us-gaap_Goodwill $ 269,465,000us-gaap_Goodwill
Property, Plant and Equipment, Gross       558,710,000us-gaap_PropertyPlantAndEquipmentGross 614,702,000us-gaap_PropertyPlantAndEquipmentGross
Hewitt Power & Communications, Inc          
Business Acquisition [Line Items]          
Acquisition payments 8,000,000us-gaap_PaymentsToAcquireBusinessesGross
/ us-gaap_BusinessAcquisitionAxis
= dy_HewittPowerCommunicationsIncMember
       
Finite-Lived Intangible Assets, Gross 5,900,000us-gaap_FiniteLivedIntangibleAssetsGross
/ us-gaap_BusinessAcquisitionAxis
= dy_HewittPowerCommunicationsIncMember
       
Cable Installation Contractors          
Business Acquisition [Line Items]          
Acquisition payments   1,500,000us-gaap_PaymentsToAcquireBusinessesGross
/ us-gaap_BusinessAcquisitionAxis
= dy_ConnectCableContractorsInc.andSystemsCommunicationsServicesInc.Member
     
Number of businesses acquired   2us-gaap_NumberOfBusinessesAcquired
/ us-gaap_BusinessAcquisitionAxis
= dy_ConnectCableContractorsInc.andSystemsCommunicationsServicesInc.Member
     
Telecommunications Specialty Construction Contractor, Canada          
Business Acquisition [Line Items]          
Acquisition payments     700,000us-gaap_PaymentsToAcquireBusinessesGross
/ us-gaap_BusinessAcquisitionAxis
= dy_TelecommunicationsSpecialtyConstructionContractorCanadaMember
   
Watts Brothers          
Business Acquisition [Line Items]          
Acquisition payments       16,400,000us-gaap_PaymentsToAcquireBusinessesGross
/ us-gaap_BusinessAcquisitionAxis
= dy_WattsBrothersCableConstructionInc.Member
 
Business Acquisition, Cost of Acquired Entity, Cash Paid For Working Capital 2,600,000dy_BusinessAcquisitionCostOfAcquiredEntityCashPaidForWorkingCapital
/ us-gaap_BusinessAcquisitionAxis
= dy_WattsBrothersCableConstructionInc.Member
       
Goodwill 1,600,000us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= dy_WattsBrothersCableConstructionInc.Member
       
Finite-Lived Customer Relationships, Gross 8,500,000us-gaap_FiniteLivedCustomerRelationshipsGross
/ us-gaap_BusinessAcquisitionAxis
= dy_WattsBrothersCableConstructionInc.Member
       
Property, Plant and Equipment, Gross $ 3,700,000us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_BusinessAcquisitionAxis
= dy_WattsBrothersCableConstructionInc.Member