General - Contributions to Revenues and Profits Since Acquisitions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Business Acquisition [Line Items]
Restructuring charges	$ 1,535	$ 204	$ 8,332	$ 862
Underground Solutions
Business Acquisition [Line Items]
Revenues	10,977		15,643
Net loss	(1,638)		(1,762)
Fyfe Europe
Business Acquisition [Line Items]
Revenues	8		8
Net loss	(98)		(98)
LMJ
Business Acquisition [Line Items]
Revenues	1,333		1,333
Net loss	(87)		(87)
Schultz Mechanical Contractors, Inc.
Business Acquisition [Line Items]
Revenues	5,611	3,970	10,321	4,487
Net loss	(59)	(19)	(400)	(26)
Restructuring charges			200
Corporate, Non-Segment | Underground Solutions
Business Acquisition [Line Items]
Net loss	(1,300)		(1,300)
Corporate, Non-Segment | Schultz Mechanical Contractors, Inc.
Business Acquisition [Line Items]
Net loss	$ (300)	$ (200)	$ (300)	$ (200)