Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales:
Products	$ 709,438	$ 691,496	$ 654,599
Service	218,016	200,242	171,827
Total net sales	927,454	891,738	826,426
Cost of sales:
Products	352,630	347,224	344,575
Service	136,039	128,884	114,485
Total cost of sales	488,669	476,108	459,060
Gross profit	438,785	415,630	367,366
Operating expenses:
Research and development	101,947	94,965	78,318
Selling, general and administrative	179,560	169,719	158,782
Restructuring, reorganization, relocation and severance	1,090	2,859	3,215
Total operating expenses	282,597	267,543	240,315
Operating income	156,188	148,087	127,051
Other expense:
Interest income	428	1,606	2,361
Interest expense	(1,890)	(4,098)	(4,037)
Other, net	(3,124)	(5,047)	(2,510)
Total other expense, net	(4,586)	(7,539)	(4,186)
Income before income taxes	151,602	140,548	122,865
Income tax expense	24,929	25,628	19,228
Net income	$ 126,673	$ 114,920	$ 103,637
Basic net income per share	$ 3.13	$ 3.02	$ 2.70
Diluted net income per share	$ 3.01	$ 2.80	$ 2.51
Cash dividends declared per share	$ 0.44	$ 0.24	$ 0.00
Shares used in per share calculations:
Basic (in shares)	40,446	38,065	38,384
Diluted (in shares)	42,395	41,728	42,047