Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue	$ 792,845	$ 709,912	$ 2,351,862	$ 2,121,494
Costs and operating expenses:
Cost of revenue (exclusive of amortization of acquired intangible assets shown below)	283,439	246,938	828,825	729,874
Research and development	66,773	64,887	202,087	192,467
Sales and marketing	122,749	122,258	370,004	383,640
General and administrative	128,365	123,216	385,435	366,167
Amortization of acquired intangible assets	10,340	9,624	31,155	28,871
Restructuring charge (benefit)	21	(300)	10,439	6,879
Total costs and operating expenses	611,687	566,623	1,827,945	1,707,898
Income from operations	181,158	143,289	523,917	413,596
Interest income	6,307	7,908	22,852	22,953
Interest expense	(17,324)	(12,127)	(51,778)	(32,689)
Other expense, net	(2,158)	(752)	(7,869)	(819)
Income before provision for income taxes	167,983	138,318	487,122	403,041
(Provision) benefit for income taxes	(8,801)	960	(41,764)	(42,718)
Loss from equity method investment	(559)	(1,388)	(1,674)	(1,388)
Net income	$ 158,623	$ 137,890	$ 443,684	$ 358,935
Net income per share:
Basic (in dollars per share)	$ 0.97	$ 0.85	$ 2.73	$ 2.20
Diluted (in dollars per share)	$ 0.95	$ 0.84	$ 2.69	$ 2.18
Shares used in per share calculations:
Basic (in shares)	162,757	162,445	162,387	163,029
Diluted (in shares)	166,519	164,558	164,990	164,788