XML 22 R57.htm IDEA: XBRL DOCUMENT v2.4.1.9
Stock-Based Awards (Details) (USD $)
In Millions, except Share data, unless otherwise specified
 6 Months Ended 12 Months Ended
Jan. 24, 2015
Jul. 26, 2014
Stock Options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized compensation expense related to stock options $ 3.9us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember		  
Total compensation cost not yet recognized, period for recognition 2 years 10 months 7 days  
RSUs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized compensation expense related to stock options 8.0us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember		  
Total compensation cost not yet recognized, period for recognition 2 years 7 months 25 days  
Granted 99,064us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember		  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 362,869us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember		 398,931us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockUnitsRSUMember
Performance RSUs    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized compensation expense related to stock options 17.6us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember		  
Total compensation cost not yet recognized, period for recognition 1 year 7 months 25 days  
Compensation expense $ 5.3dy_PotentialCompensationExpenseForPerformanceBasedSharesIfPerformanceGoalsAreMet
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember		  
RSUs outstanding 357,331dy_ShareBasedCompensationByShareBasedPaymentAwardEquityAwardsOtherThanOptionsTargetAmount
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember		  
Granted 416,987us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember		  
Forfeited or cancelled   312,163dy_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsCancelledinPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
Share-based Compensation by Share-based Payment Award, Equity Awards Other than Options, Target Shares Expected to be Canceled   48,313dy_SharebasedCompensationbySharebasedPaymentAwardEquityAwardsOtherthanOptionsTargetSharesExpectedtobeCanceled
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
Share-based Compensation by Share-based Payment Award, Equity Awards Other than Options, Supplemental Shares Expected to be Canceled   263,850dy_SharebasedCompensationbySharebasedPaymentAwardEquityAwardsOtherthanOptionsSupplementalSharesExpectedtobeCanceled
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 960,251us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember		 1,190,184us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_PerformanceSharesMember
Target Shares    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 730,046us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= dy_TargetSharesMember		  
Supplemental Shares    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Granted 59,656us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= dy_SupplementalSharesMember		  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 230,205us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= dy_SupplementalSharesMember