Condensed Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues:
Products	$ 159,465	$ 134,238	$ 455,846	$ 368,901
Services	31,395	20,797	88,708	60,795
Total revenues	190,860	155,035	544,554	429,696
Cost and expenses:
Products	103,614	80,713	287,567	216,219
Services	18,207	15,774	49,629	42,381
Total cost of sales	121,821	96,487	337,196	258,600
Selling, general and administrative	20,764	18,274	58,614	52,572
Engineering and product development	9,552	8,498	28,640	25,725
Total cost and expenses	152,137	123,259	424,450	336,897
Operating income	38,723	31,776	120,104	92,799
Interest income	148	84	329	269
Interest expense	(7)	(15)	(21)	(37)
Income before income taxes	38,864	31,845	120,412	93,031
Income tax provision	9,207	8,582	32,155	25,888
Net income	$ 29,657	$ 23,263	$ 88,257	$ 67,143
Earnings per common share:
Basic	$ 0.73	$ 0.58	$ 2.19	$ 1.68
Diluted	$ 0.73	$ 0.58	$ 2.18	$ 1.67
Weighted average common shares outstanding:
Basic	40,423	40,059	40,292	40,055
Diluted	40,589	40,296	40,492	40,311