Consolidated 50% Owned Subsidiaries, including Variable Interest Entities ("VIE") - Components of Noncontrolling Interest Subject to Mandatory Redemption (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Noncontrolling Interest [Abstract]
Members’ interest subject to mandatory redemption	$ 40,000	$ 40,000
Net accumulated earnings	9,343	7,386
Total liability	$ 49,343	$ 47,386

The net amount of undistributed earnings (distributed earnings) of domestic subsidiaries or domestic joint ventures intended to be permanent.

No definition available.

Name:	strl_UndistributedEarningsOfDomesticSubsidiariesNet
Namespace Prefix:	strl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant