CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues:
Products	$ 731,617	$ 610,218	$ 511,650
Services	140,755	122,813	89,692
Total revenues	872,372	733,031	601,342
Cost and expenses:
Products	436,359	384,513	303,995
Services	77,547	67,153	57,853
Total cost of sales	513,906	451,666	361,848
Selling, general and administrative	94,806	82,218	70,510
Engineering and product development	40,115	37,455	34,626
Special items			4,719
Total costs and expenses	648,827	571,339	471,703
Operating income	223,545	161,692	129,639
Interest income	587	462	418
Interest expense	(35)	(32)	(53)
Income before income taxes	224,097	162,122	130,004
Income tax provision	54,270	42,913	34,737
Net income	$ 169,827	$ 119,209	$ 95,267
Earnings per common share:
Basic	$ 4.18	$ 2.96	$ 2.38
Diluted	$ 4.16	$ 2.94	$ 2.36
Weighted average common shares outstanding:
Basic	40,648	40,332	40,071
Diluted	40,865	40,523	40,322