Property, Plant and Equipment and Railcars on Leases, net (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Components of property, plant and equipment
Property, plant and equipment, net	$ 169,628	$ 177,051
Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	424,653	421,435
Less accumulated depreciation	(255,025)	(244,384)
Property, plant and equipment, net	169,628	177,051
Railcar Leasing [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	1,100,122	996,422
Less accumulated depreciation	(105,301)	(88,412)
Property, plant and equipment, net	994,821	908,010
Buildings [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	185,594	182,970
Machinery and equipment [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	233,111	232,171
Land [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	4,813	4,328
Construction in process [Member] | Operations / Corporate: [Member]
Components of property, plant and equipment
Property, plant and equipment, gross	$ 1,135	$ 1,966