Operating Segment and Sales Concentrations (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) segment	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment			3
Total revenues	$ 146,528	$ 109,020	$ 262,766	$ 223,701
Operating Income (Loss)	17,361	22,150	38,402	44,065
Asset Impairment Charges	3,554	0	3,554	0
Total Assets	1,480,807		1,480,807		$ 1,473,426
Corporate/Eliminations [Member]
Segment Reporting Information [Line Items]
Total Assets	(169,642)		(169,642)		(174,211)
Manufacturing [Member]
Segment Reporting Information [Line Items]
Total revenues	91,719	110,529	176,635	231,359
Operating Income (Loss)	2,269	7,299	6,677	16,450
Total Assets	222,575		222,575		212,508
Railcar Leasing [Member]
Segment Reporting Information [Line Items]
Total revenues	34,804	33,717	68,925	67,552
Operating Income (Loss)	13,991	18,690	31,414	37,500
Asset Impairment Charges	(3,600)		(3,600)
Total Assets	1,364,687		1,364,687		1,375,315
Railcar Services [Member]
Segment Reporting Information [Line Items]
Total revenues	24,391	22,099	44,471	42,551
Operating Income (Loss)	2,985	3,329	4,681	5,045
Total Assets	63,187		63,187		$ 59,814
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	(4,534)	(4,953)	(8,312)	(9,225)
Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	(4,386)	(57,325)	(27,265)	(117,761)
Operating Income (Loss)	2,650	(2,215)	3,942	(5,705)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Asset Impairment Charges	8,000		8,000
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	146,528	109,020	262,766	223,701
Operating Segments [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Total revenues	89,440	55,087	153,581	115,813
Operating Segments [Member] | Railcar Leasing [Member]
Segment Reporting Information [Line Items]
Total revenues	34,804	33,717	68,925	67,552
Operating Segments [Member] | Railcar Services [Member]
Segment Reporting Information [Line Items]
Total revenues	22,284	20,216	40,260	40,336
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	2,279	55,442	23,054	115,546
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	2,107	1,883	4,211	2,215
Intersegment Eliminations [Member] | Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	$ (4,386)	$ (57,325)	$ (27,265)	$ (117,761)