Goodwill and Identified Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 293,023
Additions to goodwill through acquisitions	3,998
Foreign currency translation	(2,529)
Goodwill, ending balance	294,492
Infrastructure Solutions [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	177,275
Additions to goodwill through acquisitions	0
Foreign currency translation	(1,800)
Goodwill, ending balance	175,475
Corrosion Protection [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	39,500
Additions to goodwill through acquisitions	0
Foreign currency translation	(729)
Goodwill, ending balance	38,771
Energy Services [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	76,248
Additions to goodwill through acquisitions	3,998
Foreign currency translation	0
Goodwill, ending balance	$ 80,246