COMMITMENTS AND VARIABLE INTEREST ENTITIES - Variable Interest Entities (Details)	3 Months Ended
Mar. 31, 2023 entity
COMMITMENTS AND VARIABLE INTEREST ENTITIES
Number of VIEs	1

Represents the information pertaining to number of variable entities.

No definition available.

Name:	wldn_NumberOfVariableInterestEntity
Namespace Prefix:	wldn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration