Goodwill and Intangible Assets Goodwill (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Mar. 31, 2015
Dec. 31, 2014
Changes in carrying amounts of goodwill      
Beginning Goodwill Gross   $ 129,350 $ 129,350
Accumulated impairment losses   (116,377) (116,377)
Goodwill Net Beginning Balance   12,973 12,973
Ending Goodwill Gross 129,350 129,350 129,350
Goodwill Net Ending Balance 12,973 12,973 12,973
Metals Segment [Member]      
Changes in carrying amounts of goodwill      
Beginning Goodwill Gross   116,377 116,377
Accumulated impairment losses   (116,377) (116,377)
Goodwill Net Beginning Balance   0 0
Ending Goodwill Gross 116,377 116,377 116,377
Goodwill Net Ending Balance 0 0 0
Plastics Segment      
Changes in carrying amounts of goodwill      
Beginning Goodwill Gross   12,973  
Accumulated impairment losses   0 0
Goodwill Net Beginning Balance   12,973  
Goodwill, Impairment Loss 0    
Ending Goodwill Gross 12,973 12,973  
Goodwill Net Ending Balance $ 12,973 $ 12,973