CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Sales and service revenue
Product sales	$ 161,435	$ 143,919	$ 157,838
Service revenues	92,605	79,437	83,358
Net sales	254,040	223,356	241,196
Cost of sales and service revenue
Cost of product sales	117,368	106,891	117,999
Cost of service revenues	77,022	64,965	70,246
Cost of sales	194,390	171,856	188,245
Gross profit	59,650	51,500	52,951
Selling, general and administrative expenses	34,726	32,435	31,678
Impairment of goodwill	0	0	3,350
Severance and restructuring	0	0	312
Income from operations	24,924	19,065	17,611
Other income (expense):
Interest expense	(669)	(696)	(1,623)
Other, net	(730)	58	10
Total other expense	(1,399)	(638)	(1,613)
Income before income taxes	23,525	18,427	15,998
Provision for income taxes	7,136	5,496	5,843
Net income	$ 16,389	$ 12,931	$ 10,155
Amounts per common share:
Net income per common share (in dollars per share)	$ 1.42	$ 1.13	$ 0.90
Net income per common share assuming dilution (in dollars per share)	$ 1.40	$ 1.11	$ 0.90
Weighted average common shares outstanding (in shares)	11,559,895	11,420,524	11,305,231
Weighted average dilutive common shares outstanding (in shares)	11,741,513	11,636,385	11,341,312