Property, Plant and Equipment and Railcars on Leases, net (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Components of property, plant and equipment
Property, plant and equipment, net	$ 165,919	$ 177,051
Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	426,446	421,435
Less accumulated depreciation	(260,527)	(244,384)
Property, plant and equipment, net	165,919	177,051
Railcar Leasing [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	1,128,471	996,422
Less accumulated depreciation	(114,233)	(88,412)
Property, plant and equipment, net	1,014,238	908,010
Buildings [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	186,272	182,970
Machinery and equipment [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	233,774	232,171
Land [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	5,037	4,328
Construction in process [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	$ 1,363	$ 1,966