Investments in and Loans to Joint Ventures (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Ohio Castings [Member]
Results of operations
Revenues	$ 5	$ 13,683	$ 4,454	$ 27,337
Gross profit (loss)	(419)	1,004	(2,399)	1,214
Net earnings/(loss)	(33)	218	(2,467)	(380)
Axis [Member]
Results of operations
Revenues	11,089	16,086	25,455	32,497
Gross profit (loss)	2,990	4,818	7,196	9,860
Net earnings/(loss)	$ 2,161	$ 3,710	$ 5,492	$ 7,564