Property, Plant and Equipment (Textual) (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Capitalized interest						$ 900
Depreciation expense			$ 11,500	$ 11,900		34,700	$ 36,000
Total impairments			0	0		6,272	0
Grain
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets held-for-sale		$ 5,300			$ 1,600
Total impairments								$ 10,900
Impairment of long-lived assets held-for-use		$ 5,600
Rail
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets held-for-use	$ 4,700
Depreciation expense on railcar assets leased to others			$ 6,100	$ 5,200		$ 18,400	$ 14,900