Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Revenue	$ 498,042	$ 395,790	$ 1,427,579	$ 1,141,942
Costs and operating expenses:
Cost of revenue	158,812	132,039	447,742	377,136
Research and development	32,583	24,857	92,869	67,359
Sales and marketing	96,215	67,811	268,742	198,326
General and administrative	81,905	66,634	239,946	183,365
Amortization of acquired intangible assets	8,403	4,859	23,654	16,653
Restructuring (benefits) charges	(115)	69	1,189	891
Total costs and operating expenses	377,803	296,269	1,074,142	843,730
Income from operations	120,239	99,521	353,437	298,212
Interest income	2,010	1,458	5,389	4,543
Interest expense	(4,482)	0	(10,939)	0
Other expense, net	(188)	(305)	(1,968)	(96)
Income before provision for income taxes	117,579	100,674	345,919	302,659
Provision for income taxes	26,424	20,918	109,078	89,521
Net income	$ 91,155	$ 79,756	$ 236,841	$ 213,138
Net income per share:
Basic (in dollars per share)	$ 0.51	$ 0.45	$ 1.33	$ 1.20
Diluted (in dollars per share)	$ 0.50	$ 0.44	$ 1.31	$ 1.17
Shares used in per share calculations:
Basic (in shares)	178,186	178,235	178,324	178,008
Diluted (in shares)	180,955	181,922	181,278	181,623