Inventories (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Inventories
Metals inventory	$ 0	$ 0
In-process inventory	0	0
Material and supplies	264	330
Inventories	264	330
Obsolescence charge reflected in shutdown costs	$ 200	$ 300