Operating Segment and Sales Concentrations (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			3
Total revenues	$ 120,746	$ 144,962	$ 344,447	$ 471,626
Earnings from operations	19,547	16,085	63,612	92,756
Total Assets	1,467,758		1,467,758		$ 1,456,250
Corporate/Eliminations [Member]
Segment Reporting Information [Line Items]
Total Assets	(176,651)		(176,651)		(112,257)
Manufacturing [Member]
Segment Reporting Information [Line Items]
Total revenues	102,067	124,829	333,426	379,066
Earnings from operations	3,733	(2,773)	20,183	35,451
Total Assets	225,157		225,157		256,622
Railcar Leasing [Member]
Segment Reporting Information [Line Items]
Total revenues	33,440	32,798	100,992	98,775
Earnings from operations	19,029	19,320	56,529	59,232
Total Assets	1,357,891		1,357,891		1,254,824
Railcar Services [Member]
Segment Reporting Information [Line Items]
Total revenues	19,840	18,785	62,391	59,700
Earnings from operations	1,941	2,797	6,986	9,364
Total Assets	61,361		61,361		$ 57,061
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Earnings from operations	(4,603)	(2,649)	(13,828)	(11,598)
Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	(34,601)	(31,450)	(152,362)	(65,915)
Earnings from operations	(553)	(610)	(6,258)	307
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	120,746	144,962	344,447	471,626
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Total revenues	68,442	93,546	184,255	314,886
Operating Segments [Member] | Railcar Leasing [Member]
Segment Reporting Information [Line Items]
Total revenues	33,440	32,798	100,992	98,775
Operating Segments [Member] | Railcar Services [Member]
Segment Reporting Information [Line Items]
Total revenues	18,864	18,618	59,200	57,965
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Intersegment Eliminations [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Total revenues	33,625	31,283	149,171	64,180
Intersegment Eliminations [Member] | Railcar Leasing [Member]
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Intersegment Eliminations [Member] | Railcar Services [Member]
Segment Reporting Information [Line Items]
Total revenues	976	167	3,191	1,735
Intersegment Eliminations [Member] | Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	$ (34,601)	$ (31,450)	$ (152,362)	$ (65,915)