Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Product sales	$ 1,346,729	$ 1,312,503	$ 1,280,507
Service sales	642,615	591,715	563,134
Total net sales	1,989,344	1,904,218	1,843,641
Cost of product sales	549,121	526,721	501,660
Cost of service sales	275,792	256,735	235,954
Total cost of sales	824,913	783,456	737,614
Gross profit	1,164,431	1,120,762	1,106,027
Selling and administrative expenses	512,707	492,965	477,270
Research and development expenses	107,726	100,536	96,004
Acquired in-process research and development (Note 2)	15,456
Purchased intangibles amortization	10,634	9,918	13,829
Litigation provisions (Note 10)			7,434
Operating income	517,908	517,343	511,490
Other expense (Note 3)		(1,575)
Interest expense	(34,191)	(30,050)	(28,073)
Interest income	7,023	4,387	4,208
Income from operations before income taxes	490,740	490,105	487,625
Provision for income taxes	59,120	40,102	26,182
Net income	$ 431,620	$ 450,003	$ 461,443
Net income per basic common share	$ 5.12	$ 5.27	$ 5.25
Weighted-average number of basic common shares	84,358	85,426	87,841
Net income per diluted common share	$ 5.07	$ 5.20	$ 5.19
Weighted-average number of diluted common shares and equivalents	85,151	86,546	88,979