Restructuring - 2016 Restructuring (Details) $ in Thousands		12 Months Ended
	Dec. 31, 2015 employee	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges		$ 12,814	$ 9,168	$ 968
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			16,100
Restructuring charges net of tax			10,300
Restructuring charges, incurred			16,100
Non-Cash Restructuring Charges			800
Cash restructuring charges			15,300
Cash		900	14,435
Utilized non-cash		0	765
Restructuring reserve		0	900
Severance and benefit related costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			7,396
Restructuring charges, incurred			7,396
Cash		645	6,751
Utilized non-cash		0	0
Restructuring reserve		0	645
Severance and benefit related costs | Restructuring Plan 2016 | Cost of revenues
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			278
Lease termination costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			1,137
Restructuring charges, incurred			1,137
Cash		125	1,012
Utilized non-cash		0	0
Restructuring reserve		0	125
Lease termination costs | Restructuring Plan 2016 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			6,478
Relocation and other moving costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			562
Restructuring charges, incurred			562
Cash		10	552
Utilized non-cash		0	0
Restructuring reserve		0	10
Relocation and other moving costs | Restructuring Plan 2016 | Restructuring charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			9,095
Other restructuring | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			7,005
Restructuring charges, incurred			7,005
Cash		120	6,120
Utilized non-cash		0	765
Restructuring reserve		$ 0	120
Other restructuring | Restructuring Plan 2016 | Other expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			249
Employee severance and lease termination | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			9,100
Infrastructure Solutions | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Estimated effect on future earnings			1,200
Restructuring and related charges			3,364
Restructuring charges, incurred			3,365
Infrastructure Solutions | Severance and benefit related costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			2,249
Infrastructure Solutions | Severance and benefit related costs | Restructuring Plan 2016 | Cost of revenues
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			0
Infrastructure Solutions | Lease termination costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			0
Infrastructure Solutions | Lease termination costs | Restructuring Plan 2016 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			559
Infrastructure Solutions | Relocation and other moving costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			307
Infrastructure Solutions | Relocation and other moving costs | Restructuring Plan 2016 | Restructuring charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			2,557
Infrastructure Solutions | Other restructuring | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			808
Infrastructure Solutions | Other restructuring | Restructuring Plan 2016 | Other expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			249
Corrosion Protection | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Estimated effect on future earnings			6,600
Restructuring and related charges			4,565
Restructuring charges, incurred			4,564
Corrosion Protection | Severance and benefit related costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			3,588
Corrosion Protection | Severance and benefit related costs | Restructuring Plan 2016 | Cost of revenues
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			278
Corrosion Protection | Lease termination costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			154
Corrosion Protection | Lease termination costs | Restructuring Plan 2016 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			483
Corrosion Protection | Relocation and other moving costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			62
Corrosion Protection | Relocation and other moving costs | Restructuring Plan 2016 | Restructuring charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			3,803
Corrosion Protection | Other restructuring | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			761
Corrosion Protection | Other restructuring | Restructuring Plan 2016 | Other expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			0
Energy Services | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Estimated effect on future earnings			5,600
Restructuring and related charges			8,171
Restructuring charges, incurred			8,171
Energy Services | Severance and benefit related costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			1,559
Energy Services | Severance and benefit related costs | Restructuring Plan 2016 | Cost of revenues
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			0
Energy Services | Lease termination costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			983
Energy Services | Lease termination costs | Restructuring Plan 2016 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			5,436
Energy Services | Relocation and other moving costs | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			193
Energy Services | Relocation and other moving costs | Restructuring Plan 2016 | Restructuring charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			2,735
Energy Services | Other restructuring | Restructuring Plan 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges			5,436
Energy Services | Other restructuring | Restructuring Plan 2016 | Other expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges, incurred			0
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