CONTINGENCIES (Details)	Jul. 16, 2014 USD ($)
CONTINGENCIES
Minimum revenue shortfall alleged in lawsuit	$ 9,000,000
Alleged cost to retain another consultant	130,000
Alleged costs associated with noticing and conducting public hearings	$ 83,052

Represents costs associated with noticing and conducting public hearings alleged in legal action.

No definition available.

Name:	wldn_LossContingencyPublicHearingCosts
Namespace Prefix:	wldn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration