Property, Plant and Equipment and Railcars on Leases, net (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Components of property, plant and equipment
Property, plant and equipment, net	$ 153,130	$ 162,535
Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	429,667	426,792
Less accumulated depreciation	(276,537)	(264,257)
Property, plant and equipment, net	153,130	162,535
Railcar Leasing [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	1,231,158	1,159,868
Less accumulated depreciation	(153,390)	(123,454)
Property, plant and equipment, net	1,077,768	1,036,414
Buildings [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	189,009	186,664
Machinery and equipment [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	231,849	233,025
Land [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	5,372	5,285
Construction in process [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	3,437	$ 1,818
Equipment Leased to Other Party [Member] | IELP Entities [Member]
Components of property, plant and equipment
Operating Leases, Future Minimum Payments Receivable Related to Affiliate	$ 7,000