Reportable Segments and Geographic Data (Schedule of Financial Data by Reporting Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2009	Mar. 31, 2009	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Net sales	$ 202,600	$ 206,700	$ 198,600	$ 206,800	$ 199,800	$ 192,200	$ 193,700	$ 180,100	$ 194,000	$ 186,700	$ 182,100	$ 174,900	$ 814,696	$ 765,769	$ 737,621
Depreciation and amortization													64,203	60,817	67,839
Operating income/(loss)													83,073	71,285	(36,126)
Interest income													2,027	1,165	741
Interest expense													(20,148)	(18,405)	(21,368)
Other income/(expense), net													(2,720)	884	49,700
Income/(loss) before income taxes													62,232	54,929	(7,053)
Paper Machine Clothing [Member]
Segment Reporting Information [Line Items]
Net sales													657,569	623,555	609,897
Depreciation and amortization													45,831	43,979	49,864
Operating income/(loss)													165,528	156,561	42,624
Engineered Fabrics [Member]
Segment Reporting Information [Line Items]
Net sales													81,642	77,465	74,908
Depreciation and amortization													2,350	5,057	5,902
Operating income/(loss)													11,230	9,101	3,047
Engineered Composites [Member]
Segment Reporting Information [Line Items]
Net sales													48,076	41,867	33,824
Depreciation and amortization													4,959	4,277	4,591
Operating income/(loss)													(4,204)	(9,176)	(6,653)
PrimaLoft Products [Member]
Segment Reporting Information [Line Items]
Net sales													27,409	22,882	18,992
Depreciation and amortization													391	373	427
Operating income/(loss)													8,540	6,610	3,689
Research Expense [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization													10,672	7,131	7,055
Operating income/(loss)													(29,007)	(26,064)	(23,849)
Unallocated Expenses [Member]
Segment Reporting Information [Line Items]
Operating income/(loss)													$ (69,014)	$ (65,747)	$ (54,984)