Investments in and Loans to Joint Ventures (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Ohio Castings [Member]
Results of operations
Revenues	$ 0	$ 15	$ 0	$ 4,469
Gross profit/(loss)	(387)	(396)	(1,299)	(2,795)
Net earnings/(loss)	(618)	(712)	(1,569)	(3,179)
Axis [Member]
Results of operations
Revenues	13,391	10,432	39,532	35,887
Gross profit/(loss)	1,928	1,448	8,082	8,644
Net earnings/(loss)	$ 1,369	$ 688	$ 6,274	$ 6,180