Segment Reporting Segment Reporting - Segment Information for Total Assets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Segment Reporting Information [Line Items]
Assets	$ 686,778		$ 679,822
Metals segment
Segment Reporting Information [Line Items]
Assets	581,881		580,570
Plastics segment
Segment Reporting Information [Line Items]
Assets	61,718		57,373
Other
Segment Reporting Information [Line Items]
Assets	$ 43,179	[1]	$ 41,879	[1]

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