Goodwill and Intangible Assets - Reconciliation Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill, gross - beginning balance			$ 344,535	$ 344,535
Goodwill, accumulated impairment loss - beginning balance			(51,512)	(51,512)
Goodwill, net - beginning balance			293,023	293,023
Additions to goodwill through acquisitions				3,998
Goodwill impairment	$ (43,500)			(43,484)	$ (51,512)	$ 0
Foreign currency translation				(4,417)
Goodwill, gross - ending balance	344,116			344,116	344,535
Goodwill, accumulated impairment loss - ending balance	(94,996)			(94,996)	(51,512)
Goodwill, net - ending balance	249,120			249,120	293,023
Schultz
Goodwill [Roll Forward]
Additions to goodwill through acquisitions		$ 400	3,600
Infrastructure Solutions
Goodwill [Roll Forward]
Goodwill, gross - beginning balance			193,344	193,344
Goodwill, accumulated impairment loss - beginning balance			(16,069)	(16,069)
Goodwill, net - beginning balance			177,275	177,275
Additions to goodwill through acquisitions				0
Goodwill impairment				0
Foreign currency translation				(2,819)
Goodwill, gross - ending balance	190,525			190,525	193,344
Goodwill, accumulated impairment loss - ending balance	(16,069)			(16,069)	(16,069)
Goodwill, net - ending balance	174,456			174,456	177,275
Corrosion Protection
Goodwill [Roll Forward]
Goodwill, gross - beginning balance			74,943	74,943
Goodwill, accumulated impairment loss - beginning balance			(35,443)	(35,443)
Goodwill, net - beginning balance			39,500	39,500
Additions to goodwill through acquisitions				0
Goodwill impairment	(10,000)			(9,957)
Foreign currency translation				(1,598)
Goodwill, gross - ending balance	73,345			73,345	74,943
Goodwill, accumulated impairment loss - ending balance	(45,400)			(45,400)	(35,443)
Goodwill, net - ending balance	27,945			27,945	39,500
Energy Services
Goodwill [Roll Forward]
Goodwill, gross - beginning balance			76,248	76,248
Goodwill, accumulated impairment loss - beginning balance			0	0
Goodwill, net - beginning balance			$ 76,248	76,248
Additions to goodwill through acquisitions				3,998
Goodwill impairment	(33,500)			(33,527)
Foreign currency translation				0
Goodwill, gross - ending balance	80,246			80,246	76,248
Goodwill, accumulated impairment loss - ending balance	(33,527)			(33,527)	0
Goodwill, net - ending balance	$ 46,719			$ 46,719	$ 76,248