Restructuring - Pre Tax Restructuring Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,789	$ 0
Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	5,244
Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,071
Lease and contract termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	678
Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	40
Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,455
Infrastructure Solutions | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,533
Infrastructure Solutions | Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	865
Infrastructure Solutions | Lease and contract termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	528
Infrastructure Solutions | Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	40
Infrastructure Solutions | Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2,100
Corrosion Protection | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,711
Corrosion Protection | Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	206
Corrosion Protection | Lease and contract termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	150
Corrosion Protection | Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0
Corrosion Protection | Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,355
Corporate, Non-Segment | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 600