General - Contributions to Revenues and Profits Since Acquisitions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Underground Solutions
Business Acquisition [Line Items]
Revenues	$ 9,520	$ 10,977	$ 16,045	$ 15,643
Net income (loss)	(356)	(1,638)	(1,675)	(1,762)
Inventory step up expense		2,400		3,600
Fyfe Europe
Business Acquisition [Line Items]
Revenues	102	8	361	8
Net income (loss)	(86)	(98)	(144)	(98)
LMJ
Business Acquisition [Line Items]
Revenues	1,023	1,333	2,360	1,333
Net income (loss)	(1,020)	$ (87)	(1,617)	(87)
Concrete Solutions
Business Acquisition [Line Items]
Revenues	1,332		2,715
Net income (loss)	1		51
Environmental Techniques
Business Acquisition [Line Items]
Revenues	1,472		1,923
Net income (loss)	(291)		(393)
Corporate, Non-Segment | Underground Solutions
Business Acquisition [Line Items]
Net income (loss)	$ 700		$ 1,100	$ 1,300