Property, Plant and Equipment and Railcars on Leases, net (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Components of property, plant and equipment
Property, plant and equipment, net	$ 155,487	$ 162,535
Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	430,227	426,792
Less accumulated depreciation	(274,740)	(264,257)
Property, plant and equipment, net	155,487	162,535
Railcar Leasing [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	1,174,851	1,159,868
Less accumulated depreciation	(140,520)	(123,454)
Property, plant and equipment, net	1,034,331	1,036,414
Buildings [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	186,394	186,664
Machinery and equipment [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	233,906	233,025
Land [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	5,357	5,285
Construction in process [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	4,570	$ 1,818
Equipment Leased to Other Party [Member] | IELP Entities [Member]
Property, Plant and Equipment [Line Items]
Operating Leases, Future Minimum Payments Receivable Related to Affiliate	$ 7,000