Segment Data (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007
Net long-lived assets:
United States	$ 411,193,000	$ 398,318,000	$ 402,937,000	$ 352,314,000	$ 337,136,000
Net property, plant, and equipment	500,204,000	484,130,000	485,024,000	423,265,000	425,989,000
Segment Data Information (Textual) [Abstract]
Income (Loss) from Continuing Operations before Income Taxes, Foreign	106,000,000	68,200,000	38,900,000
Canada [Member]
Net long-lived assets:
Foreign Country	84,210,000	80,978,000	78,502,000	67,731,000	85,532,000
Mexico [Member]
Net long-lived assets:
Foreign Country	$ 4,801,000	$ 4,834,000	$ 3,585,000	$ 3,220,000	$ 3,321,000