Restructuring - Recognized Cost Restructuring Activities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		14 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Goodwill impairment	$ 1,389	$ 45,390	$ 1,389	$ 45,390
Definite-lived intangible asset impairment	870	41,032	870	41,032
Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	7,423	6,737	15,580	6,737
Definite-lived intangible asset impairment					$ 86,400
Restructuring charges, cash	2,300	6,600	7,400	6,600
Restructuring charges, non-cash	5,100	100	8,200	100
Restructuring 2017 | Cost of Revenue
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	705	45	705	45
Restructuring 2017 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	3,018	1,253	7,846	1,253
Goodwill impairment	1,389	0	1,389	0
Definite-lived intangible asset impairment	870	0	870	0
Restructuring 2017 | Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,219	5,439	4,548	5,439
Restructuring 2017 | Other expense
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	222	0	222	0
Infrastructure Solutions
Restructuring Cost and Reserve [Line Items]
Goodwill impairment		45,400	1,389	45,400
Definite-lived intangible asset impairment		41,000		41,000
Infrastructure Solutions | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	6,269	4,573	12,356	4,573
Infrastructure Solutions | Restructuring 2017 | Cost of Revenue
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	138	30	138	30
Infrastructure Solutions | Restructuring 2017 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	2,466	1,153	5,776	1,153
Goodwill impairment	1,389	0	1,389	0
Definite-lived intangible asset impairment	870	0	870	0
Infrastructure Solutions | Restructuring 2017 | Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,184	3,390	3,961	3,390
Infrastructure Solutions | Restructuring 2017 | Other expense
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	222	0	222	0
Corrosion Protection
Restructuring Cost and Reserve [Line Items]
Goodwill impairment			0
Corrosion Protection | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,154	2,164	3,224	2,164
Corrosion Protection | Restructuring 2017 | Cost of Revenue
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	567	15	567	15
Corrosion Protection | Restructuring 2017 | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	552	100	2,070	100
Goodwill impairment	0	0	0	0
Definite-lived intangible asset impairment	0	0	0	0
Corrosion Protection | Restructuring 2017 | Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	35	2,049	587	2,049
Corrosion Protection | Restructuring 2017 | Other expense
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	$ 0	$ 0	$ 0	$ 0