Property, Plant and Equipment (Details Textual) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Property, Plant and Equipment [Line Items]
Depreciation expense		$ 12.0	$ 11.6	$ 24.1	$ 23.8
Depreciation expense on railcar assets leased to others		$ 5.0	$ 4.7	$ 9.7	$ 9.3
Retail
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets	$ 6.0
Capitalized computer software, impairments	0.5
Plant Nutrient
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets	$ 2.3