Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues:
Products	$ 610,218	$ 511,650	$ 486,050
Services	122,813	89,692	80,201
Total revenues	733,031	601,342	566,251
Cost and expenses:
Products	384,513	303,995	272,619
Services	67,153	57,853	49,988
Total cost of sales	451,666	361,848	322,607
Selling, general and administrative	82,218	70,510	61,069
Engineering and product development	37,455	34,626	29,202
Special items		4,719	14,660
Total costs and expenses	571,339	471,703	427,538
Operating income	161,692	129,639	138,713
Interest income	462	418	321
Interest expense	(32)	(53)	(131)
Income before income taxes	162,122	130,004	138,903
Income tax provision	42,913	34,737	36,677
Net income	$ 119,209	$ 95,267	$ 102,226
Earnings per common share:
Basic	$ 2.96	$ 2.38	$ 2.57
Diluted	$ 2.94	$ 2.36	$ 2.55
Weighted average common shares outstanding:
Basic	40,332	40,071	39,828
Diluted	40,523	40,322	40,060