Segment Information (Textual) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments (business segments) | segment									4
Number of consolidated segments | segment									1
Number of segments accounted for as equity method investments | segment									3
Sales and merchandising revenues	$ 812,662	$ 685,579	$ 911,402	$ 635,739	$ 1,004,072	$ 836,595	$ 993,662	$ 852,016	$ 3,045,382	$ 3,686,345	$ 3,924,790
Rail Group assets leased to others, net	521,785				423,443				521,785	423,443
Other
Segment Reporting Information [Line Items]
Sales and merchandising revenues									0	47,871	134,229
Canada | Grain
Segment Reporting Information [Line Items]
Sales and merchandising revenues									202,700	166,200	78,300
Canada | Rail
Segment Reporting Information [Line Items]
Sales and merchandising revenues									10,700	13,300	$ 13,200
Canada | Railcar | Rail
Segment Reporting Information [Line Items]
Rail Group assets leased to others, net	$ 23,200				$ 21,200				$ 23,200	$ 21,200
Customer Concentration Risk | Revenues
Segment Reporting Information [Line Items]
Concentration risk percentage									10.00%