XML 55 R43.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Basis of Presentation (Details) | 3 Months Ended
--- | ---
Apr. 28, 2018 segment
Basis of Presentation [Abstract] |
Number of reportable segments | 1

X
- Definition Basis of Presentation [Abstract] + References No definition available. + Details
Name: | dy_BasisofPresentationAbstract
Namespace Prefix: | dy_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration