Inventories (Details) (USD $)	Sep. 26, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Aluminum and steel coil	$ 80,783,000	$ 58,153,000
Raw materials	17,782,000	15,291,000
Work in process	3,283,000	1,936,000
Finished products	18,330,000	14,380,000
Inventories, net	120,178,000	89,760,000
Inventory valuation reserves	$ (3,100,000)	$ (2,400,000)