Acquisitions (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Oct. 24, 2011	Sep. 30, 2012 Terphane [Member]	Mar. 31, 2012 Terphane [Member]	Dec. 31, 2011 Terphane [Member]	Sep. 30, 2012 Terphane [Member]	Oct. 24, 2011 Terphane [Member]	Oct. 01, 2012 AACOA [Member]
Business Acquisition [Line Items]
Percentage of outstanding equity interests acquired										100.00%	100.00%
Total purchase price					$ 182,761,000						$ 50,800,000
Post-closing adjustment paid							3,300,000
Available cash used to fund purchase price								57,700,000
Financing used to fund purchase price								125,000,000
Financing used to fund purchase price from existing credit facility											350,000,000
Sales	218,809,000	202,590,000	652,120,000	595,080,000		36,000,000			105,400,000
Net income	$ 7,427,000	$ 12,736,000	$ 17,778,000	$ 25,107,000		$ 5,700,000			$ 11,800,000