Property, Plant and Equipment (Textual) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Capitalized interest	$ 1.1		$ 1.7
Depreciation expense	17.9	$ 11.6
Rail
Property, Plant and Equipment [Line Items]
Depreciation expense on railcar assets leased to others	$ 6.7	$ 6.2