Goodwill and Intangible Assets - Goodwill (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Goodwill
Beginning Balance, Goodwill	$ 520.7
Foreign currency translation adjustments	(2.3)
Goodwill purchase price adjustment	18.7
Ending Balance, Goodwill	537.1
Beginning Balance, Accumulated goodwill impairment loss	147.1
Ending Balance, Accumulated goodwill impairment loss	147.1
VRV
Goodwill
Beginning Balance, Goodwill	63.2
Goodwill purchase price adjustment	17.9
Ending Balance, Goodwill	81.1
Skaff
Goodwill
Goodwill purchase price adjustment	0.8
Energy & Chemicals
Goodwill
Beginning Balance, Goodwill	295.8
Foreign currency translation adjustments	(0.6)
Ending Balance, Goodwill	302.9
Beginning Balance, Accumulated goodwill impairment loss	64.6
Ending Balance, Accumulated goodwill impairment loss	64.6
Energy & Chemicals | VRV
Goodwill
Goodwill purchase price adjustment	7.7
D&S West
Goodwill
Beginning Balance, Goodwill	151.3
Foreign currency translation adjustments	0.0
Goodwill purchase price adjustment	0.8
Ending Balance, Goodwill	152.1
Beginning Balance, Accumulated goodwill impairment loss	82.5
Ending Balance, Accumulated goodwill impairment loss	82.5
D&S East
Goodwill
Beginning Balance, Goodwill	73.6
Foreign currency translation adjustments	(1.7)
Ending Balance, Goodwill	82.1
Beginning Balance, Accumulated goodwill impairment loss	0.0
Ending Balance, Accumulated goodwill impairment loss	0.0
D&S East | VRV
Goodwill
Goodwill purchase price adjustment	$ 10.2