Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenues from affiliates included in manufacturing	$ 269,563	$ 245,891	$ 250,455
Revenues from affiliates included in railcar services	24,880	19,304	17,167
Interest income from related parties	$ 2,105	$ 2,429	$ 2,678