Restructuring - Pre Tax Restructuring Cost (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 5,439,000	$ 212,000	$ 5,439,000	$ 8,544,000
Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	6,737,000
Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,287,000	$ 0	14,791,000	$ 16,100,000
Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	5,070,000
Severance and benefit related costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		146,000		6,939,000
Lease termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	340,000
Lease termination costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges				969,000
Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	29,000
Relocation and other moving costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		66,000		569,000
Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,298,000
Other restructuring | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,075,000		6,314,000
Infrastructure Solutions | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4,573,000
Infrastructure Solutions | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		(31,000)		3,340,000
Infrastructure Solutions | Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,140,000
Infrastructure Solutions | Severance and benefit related costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		0		2,256,000
Infrastructure Solutions | Lease termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	250,000
Infrastructure Solutions | Lease termination costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges				0
Infrastructure Solutions | Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0
Infrastructure Solutions | Relocation and other moving costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		0		307,000
Infrastructure Solutions | Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,183,000
Infrastructure Solutions | Other restructuring | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		(31,000)		777,000
Corrosion Protection | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2,164,000
Corrosion Protection | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		178,000		3,872,000
Corrosion Protection | Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,930,000
Corrosion Protection | Severance and benefit related costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		48,000		3,182,000
Corrosion Protection | Lease termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	90,000
Corrosion Protection | Lease termination costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges				0
Corrosion Protection | Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	29,000
Corrosion Protection | Relocation and other moving costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		0		62,000
Corrosion Protection | Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	115,000
Corrosion Protection | Other restructuring | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		130,000		628,000
Energy Services | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,140,000		7,579,000
Energy Services | Severance and benefit related costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		98,000		1,501,000
Energy Services | Lease termination costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges				969,000
Energy Services | Relocation and other moving costs | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		66,000		200,000
Energy Services | Other restructuring | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		976,000		4,909,000
Corporate, Non-Segment | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 800,000
Corporate, Non-Segment | Restructuring 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 100,000		$ 1,200,000