Segment Reporting Segment Reporting - Segment Information for Total Assets (Details) - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Assets		$ 516,962	$ 587,976
Metals segment
Segment Reporting Information [Line Items]
Assets		420,714	489,563
Plastics segment
Segment Reporting Information [Line Items]
Assets		59,253	60,970
Other
Segment Reporting Information [Line Items]
Assets	[1]	$ 36,995	$ 37,443

[1] “Other” — Total assets consist of the Company's investment in joint venture.