General - Contributions to Revenues and Profits Since Acquisitions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business Acquisition [Line Items]
Restructuring charges	$ 212	$ 172	$ 8,544	$ 1,034
Underground Solutions
Business Acquisition [Line Items]
Revenues	8,273		23,916
Net income (loss)	101		(1,661)
Fyfe Europe
Business Acquisition [Line Items]
Revenues	15		23
Net income (loss)	(202)		(300)
LMJ
Business Acquisition [Line Items]
Revenues	1,446		2,779
Net income (loss)	(134)		(221)
Concrete Solutions
Business Acquisition [Line Items]
Revenues	1,344		1,344
Net income (loss)	68		68
Schultz Mechanical Contractors, Inc.
Business Acquisition [Line Items]
Revenues	6,777	3,718	17,098	8,205
Net income (loss)	193	57	(207)	31
Restructuring charges			200
Corporate, Non-Segment | Underground Solutions
Business Acquisition [Line Items]
Net income (loss)	(300)		(1,600)
Corporate, Non-Segment | Schultz Mechanical Contractors, Inc.
Business Acquisition [Line Items]
Net income (loss)	$ (300)	$ (200)	$ (600)	$ (300)