Restructuring - 2016 Restructuring Textual (Details) $ in Thousands		12 Months Ended
	Dec. 31, 2015 employee	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges		$ 6,894	$ 12,814	$ 9,168
Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Estimated effect on future earnings				17,400
Total headcount reduction | employee	964
Number of positions eliminated (percent)	15.50%
Restructuring and related charges			$ 0	16,100
Restructuring charges net of tax				10,300
Employee severance and lease termination | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges				9,100
Infrastructure Solutions
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges				2,900
Infrastructure Solutions | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Estimated effect on future earnings				1,200
Restructuring and related charges				3,364
Corrosion Protection | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Estimated effect on future earnings				6,600
Restructuring and related charges				4,565
Energy Services | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Estimated effect on future earnings				5,600
Restructuring and related charges				8,171
Corporate, Non-Segment | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Estimated effect on future earnings				4,000
Restructuring and related charges				$ 1,400