Foreign Operations and Sales (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Foreign Operations and Sales [Abstract]
Domestic gross sales									$ 109,729	$ 83,407	$ 71,363
Foreign gross sales									168,202	171,068	155,073
Domestic long-lived assets	44,085				34,885				44,085	34,885	36,691
Foreign long-lived assets	149,133				145,735				149,133	145,735	156,173
Total long-lived assets	193,218				180,620				193,218	180,620	192,864
Export sales, included in domestic gross sales									32,872	31,605	18,529
Major customer (in hundredths)									12.50%	10.80%	12.80%
Revenues from External Customers and Long-Lived Assets [Line Items]
Total gross sales	70,389	59,841	77,142	70,559	67,134	58,203	67,484	61,654	277,931	254,475	226,436
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total gross sales									150,678	156,814	127,009
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total gross sales									105,439	75,979	78,497
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total gross sales									12,827	10,448	12,554
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total gross sales									$ 8,987	$ 11,234	$ 8,376