Restructuring - Recognized Cost Restructuring Activities (Details) - Restructuring 2017 $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	$ 5,244
Restructuring charges, cash	2,800
Restructuring charges, non-cash	2,400
Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	3,455
Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,789
Infrastructure Solutions
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	3,533
Infrastructure Solutions | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	2,100
Infrastructure Solutions | Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,433
Corrosion Protection
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,711
Corrosion Protection | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,355
Corrosion Protection | Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	$ 356