Gain (loss) on sales or impairment of long lived assets (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2016	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges				$ (0.8)	$ (1.5)	$ 0.0
Gain (Loss) on Sale of Property Plant Equipment		$ 0.6	$ 3.7	9.2	(0.6)	3.1
Gain Loss On Sale Or Impairment Of Long Lived Assets, Net				8.4	(2.1)	$ 3.1
Impaired Assets to be Disposed of by Method Other than Sale, Amount of Impairment Loss				0.8	1.2
Other Asset Impairment Charges					$ 0.3
Exchange of Long Lived Assets [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Gain (Loss) on Sale of Property Plant Equipment	$ 10.6
Disposition of Various Long Lived Assets [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Gain (Loss) on Sale of Property Plant Equipment				$ (1.4)