Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended			12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Manufacturing (including revenues from affiliates of $245,891, $250,455 and $103,679 in 2014, 2013 and 2012, respectively)				$ 600,326	$ 646,100	$ 633,547
Railcar leasing				65,108	31,871	13,444
Railcar services (including revenues from affiliates of $19,304, $17,167 and $21,442 in 2014, 2013 and 2012, respectively)				67,572	72,621	64,732
Total revenues	150,540	162,842	237,509	733,006	750,592	711,723
Cost of revenues:
Manufacturing				(455,547)	(503,178)	(506,083)
Railcar leasing				(23,733)	(13,394)	(5,906)
Railcar services				(54,386)	(55,408)	(51,383)
Total cost of revenues				(533,666)	(571,980)	(563,372)
Gross profit	47,927	46,849	58,670	199,340	178,612	148,351
Selling, general and administrative				(29,420)	(27,705)	(26,931)
Gain (Loss) on Disposition of Other Assets				138	0	0
Earnings from operations				170,058	150,907	121,420
Interest income (including income from related parties of $2,429, $2,678 and $2,902 in 2014, 2013 and 2012, respectively)				2,517	2,716	3,003
Interest expense				(7,622)	(7,337)	(17,765)
Loss on debt extinguishment				(1,896)	(392)	(2,267)
Other (loss) income				(20)	2,037	1,905
Earnings (loss) from joint ventures				1,570	(8,595)	(451)
Earnings before income taxes				164,607	139,336	105,845
Income tax expense				(65,074)	(52,440)	(42,022)
Net earnings	$ 22,723	$ 23,824	$ 32,216	$ 99,533	$ 86,896	$ 63,823
Net earnings per common share—basic and diluted (in dollars per share)	$ 1.06	$ 1.12	$ 1.51	$ 4.66	$ 4.07	$ 2.99
Weighted average common shares outstanding - basic and diluted (in shares)				21,352	21,352	21,352
Cash dividends declared per common share (in dollars per share)	$ 0.25	$ 0.25	$ 0.25	$ 1.6	$ 1	$ 0.25