Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net sales:
Product	$ 1,054,849	$ 955,613	$ 807,386
Software maintenance	87,494	81,667	65,834
GSA accrual	1,349	(13,107)
Total net sales	1,143,692	1,024,173	873,220
Cost of sales:
Product	274,839	235,839	195,096
Software maintenance	5,435	5,125	4,987
Total cost of sales	280,274	240,964	200,083
Gross profit	863,418	783,209	673,137
Operating expenses:
Sales and marketing	431,468	388,768	319,606
Research and development	222,994	199,071	158,149
General and administrative	85,239	82,658	67,069
Acquisition related adjustment	6,783
Total operating expenses	746,484	670,497	544,824
Operating income	116,934	112,712	128,313
Other income (expense):
Interest income	716	1,319	1,391
Net foreign exchange loss	(2,246)	(2,755)	(2,585)
Other (expense) income, net	(567)	(142)	993
Income before income taxes	114,837	111,134	128,112
Provision for income taxes	24,700	17,062	18,996
Net income	$ 90,137	$ 94,072	$ 109,116
Basic earnings per share	$ 0.74	$ 0.79	$ 0.93
Weighted average shares outstanding - basic	121,973	119,836	116,973
Diluted earnings per share	$ 0.73	$ 0.78	$ 0.92
Weighted average shares outstanding – diluted	122,977	121,220	118,572
Dividends declared per share	$ 0.56	$ 0.40	$ 0.35