Business Segments (Schedule Of Net Sales By Product Group) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Revenue from External Customer [Line Items]
Net Sales by Product Group	$ 923,033	[1],[2]	$ 930,721	[1],[2]	$ 857,342	[1],[2]
Film Products
Revenue from External Customer [Line Items]
Net Sales by Product Group	578,687		621,239		611,877
Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	344,346		309,482		245,465
Personal care materials | Film Products
Revenue from External Customer [Line Items]
Net Sales by Product Group	317,080		339,559		327,161
Flexible packaging films | Film Products
Revenue from External Customer [Line Items]
Net Sales by Product Group	114,348		125,712		138,028
Surface protection films | Film Products
Revenue from External Customer [Line Items]
Net Sales by Product Group	90,129		90,182		69,627
Polyethylene overwrap and polypropylene films | Film Products
Revenue from External Customer [Line Items]
Net Sales by Product Group	44,263		56,590		63,796
Films for other markets | Film Products
Revenue from External Customer [Line Items]
Net Sales by Product Group	12,867		9,196		13,265
Subtotal | Film Products
Revenue from External Customer [Line Items]
Net Sales by Product Group	578,687		621,239		611,877
Nonresidential building & construction | Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	200,707		179,437		165,159
Consumer durables | Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	44,897		39,565		12,259
Residential building & construction | Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	21,470		22,055		23,555
Machinery & equipment | Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	26,907		21,936		8,773
Automotive | Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	22,272		19,919		11,757
Distribution | Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	15,318		13,115		15,227
Electrical | Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	12,775		13,455		8,735
Subtotal | Aluminum Extrusions
Revenue from External Customer [Line Items]
Net Sales by Product Group	$ 344,346		$ 309,482		$ 245,465

[1] The difference between total consolidated sales as reported in the consolidated statements of income and segment, geographic and product group net sales reported in this note is freight of $28.8 million in 2014, $28.6 million in 2013 and $24.8 million in 2012.

[2] Information on exports and foreign operations are provided on the previous page. Cash and cash equivalents includes funds held in locations outside the U.S. of $40.5 million and $38.6 million at December 31, 2014 and 2013, respectively. Export sales relate almost entirely to Film Products. Operations outside the U.S. in The Netherlands, Hungary, China, Brazil and India also relate to Film Products. Sales from locations in The Netherlands and Hungary are primarily to customers located in Europe. Sales from locations in China (Guangzhou and Shanghai) are primarily to customers located in China, but also include other customers in Asia.