Derivative Financial Instruments (Narrative) (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2014 USD ($)	Mar. 31, 2014 Aluminum Futures Contracts USD ($) lb	Dec. 31, 2013 Aluminum Futures Contracts USD ($) lb	Mar. 31, 2014 Film Products Foreign Currency Contract Forward Contract USD ($)	Mar. 31, 2014 Film Products Foreign Currency Contract Forward Contract EUR (€)	Dec. 31, 2013 Film Products Foreign Currency Contract Forward Contract USD ($)	Dec. 31, 2013 Film Products Foreign Currency Contract Forward Contract EUR (€)	Mar. 31, 2014 Derivatives Not Designated As Hedging Instruments Aluminum Futures Contracts USD ($)	Dec. 31, 2013 Derivatives Not Designated As Hedging Instruments Aluminum Futures Contracts USD ($)
Derivative [Line Items]
Notional Amount		$ 8,600,000	$ 8,000,000		€ 2,000,000		€ 2,100,000
Weight of aluminum that hedged future purchase of aluminum to meet fixed - price forward sales contract obligations, lbs		8,900,000	8,400,000
Net asset (liability), Fair Value		154,000	(147,000)	7,000		47,000		0	0
Amounts of unrealized after-tax losses on derivative instruments	$ (100,000)