Property, Plant and Equipment (Details Textual) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation expense		$ 11.6	$ 12.1
Depreciation expense on railcar assets leased to others		$ 6.2	$ 4.7
Retail
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets held-for-use				$ 10.9
Grain
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets held-for-use	$ 5.6
Impairment of long-lived assets held-for-sale	$ 5.3