Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
Segment Information
Number of reportable segments			3
Segment Information
Net sales	$ 177,812	$ 165,614	$ 310,348	$ 289,434
Sales to Other Segments	3,703	2,930	7,217	5,273
Income (Loss) from Operations	31,208	33,937	43,490	51,030
Total Assets	864,575	842,517	864,575	842,517	874,709
Cash and cash equivalents	262,013	219,763	262,013	219,763	335,049	250,381
North America
Segment Information
Net sales	139,112	134,963	243,734	235,494
Sales to Other Segments	1,490	966	2,812	1,609
Income (Loss) from Operations	30,793	32,890	45,843	53,368
Total Assets	595,842	549,130	595,842	549,130	557,762
Europe
Segment Information
Net sales	35,648	28,481	61,446	49,592
Sales to Other Segments	169	15	250	67
Income (Loss) from Operations	2,650	2,534	1,196	698
Total Assets	140,572	116,637	140,572	116,637	123,669
Asia/Pacific
Segment Information
Net sales	2,815	2,170	4,692	4,348
Sales to Other Segments	2,044	1,949	4,155	3,597
Income (Loss) from Operations	(552)	(117)	(1,265)	(309)
Total Assets	25,461	21,327	25,461	21,327	25,576
Administrative and all other
Segment Information
Net sales	237		476
Income (Loss) from Operations	(1,683)	(1,370)	(2,284)	(2,727)
Total Assets	102,700	155,423	102,700	155,423	167,702
Assets of discontinued operations included in Administrative and all other segment		32,600		32,600
Cash and cash equivalents	$ 191,500	$ 173,600	$ 191,500	$ 173,600	$ 274,600