XML 57 R45.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Significant Accounting Policies and Estimates - Revenue Recognition (Details) | 6 Months Ended
--- | ---
Jul. 28, 2018
Revenue from External Customer [Line Items] |
Composite Revenue, percentage | 5.00%
Revenue Recognized Using Cost To Cost Percentage of Completion Method |
Revenue from External Customer [Line Items] |
Percentage of Revenue | 2.50%

X
- Definition Composite Revenue, Percentage + References No definition available. + Details
Name: | dy_CompositeRevenuePercentage
Namespace Prefix: | dy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount considered as a portion of total revenue for the fiscal period. + References No definition available. + Details
Name: | dy_PercentageofRevenue
Namespace Prefix: | dy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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_EntityWideInformationRevenueFromExternalCustomerLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ProductOrServiceAxis=dy_RevenueRecognizedUsingCostToCostPercentageofCompletionMethodMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |