CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues:
Products	$ 135,194	$ 187,524
Services	31,367	38,478
Total revenues	166,561	226,002
Cost of sales:
Products	76,922	106,007
Services	16,174	19,131
Total cost of sales	93,096	125,138
Selling, general and administrative	13,221	16,958
Engineering and product development	10,901	12,213
Total costs and expenses	117,218	154,309
Operating income	49,343	71,693
Interest income	482	49
Interest expense	(4)	(3)
Income before income taxes	49,821	71,739
Income tax provision	13,052	18,075
Net income	$ 36,769	$ 53,664
Earnings per common share:
Basic (in dollars per share)	$ 0.97	$ 1.38
Diluted (in dollars per share)	$ 0.97	$ 1.38
Weighted average common shares outstanding:
Basic (in shares)	37,752	38,773
Diluted (in shares)	37,847	38,940