Inventories (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Inventories [Line Items]
Inventories stated on the LIFO basis	$ 12.2	$ 10.0
Inventories stated value below replacement costs	18.3	15.8
Cost of goods sold stated at below current replacement costs			2.7
Film Products
Inventories [Line Items]
Cost of goods sold stated at below current replacement costs	1.0	0.9	1.1
Aluminum Extrusions
Inventories [Line Items]
Cost of goods sold stated at below current replacement costs			$ 1.6