Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue	$ 2,893,617	$ 2,714,474	$ 2,489,035
Costs and operating expenses:
Cost of revenue (exclusive of amortization of acquired intangible assets shown below)	987,624	953,485	875,837
Research and development	261,365	246,165	222,434
Sales and marketing	523,883	517,353	481,522
General and administrative	516,093	574,067	509,165
Amortization of acquired intangible assets	38,581	33,311	30,904
Restructuring charge	17,153	27,594	54,884
Total costs and operating expenses	2,344,699	2,351,975	2,174,746
Income from operations	548,918	362,499	314,289
Interest income	34,355	26,940	17,855
Interest expense	(49,364)	(43,202)	(18,839)
Other (expense) income, net	(1,428)	(3,148)	887
Income before provision for income taxes	532,481	343,089	314,192
Provision for income taxes	(53,350)	(44,716)	(91,426)
Loss from equity method investment	(1,096)	0	0
Net income	$ 478,035	$ 298,373	$ 222,766
Net income per share:
Basic (in dollars per share)	$ 2.94	$ 1.78	$ 1.30
Diluted (in dollars per share)	$ 2.90	$ 1.76	$ 1.29
Shares used in per share calculations:
Basic (in shares)	162,706	167,312	171,559
Diluted (in shares)	164,573	169,188	172,711