CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Revenue	$ 852,824	$ 794,715	$ 1,695,532	$ 1,559,017
Costs and operating expenses:
Cost of revenue (exclusive of amortization of acquired intangible assets shown below)	320,000	276,804	626,687	545,386
Research and development	77,255	64,090	159,300	135,314
Sales and marketing	111,894	123,469	228,248	247,255
General and administrative	134,295	129,709	271,010	257,070
Amortization of acquired intangible assets	12,060	10,381	23,487	20,815
Restructuring (benefit) charge	(2,114)	(167)	5,002	10,418
Total costs and operating expenses	653,390	604,286	1,313,734	1,216,258
Income from operations	199,434	190,429	381,798	342,759
Interest income	4,736	9,502	9,314	16,545
Interest expense	(18,037)	(17,249)	(35,871)	(34,454)
Other expense, net	(811)	(1,603)	(1,628)	(5,711)
Income before provision for income taxes	185,322	181,079	353,613	319,139
Provision for income taxes	(18,009)	(18,671)	(29,907)	(32,963)
Loss from equity method investment	(10,816)	(493)	(11,514)	(1,115)
Net income	$ 156,497	$ 161,915	$ 312,192	$ 285,061
Net income per share:
Basic (in dollars per share)	$ 0.96	$ 1.00	$ 1.91	$ 1.76
Diluted (in dollars per share)	$ 0.94	$ 0.98	$ 1.88	$ 1.74
Shares used in per share calculations:
Basic (in shares)	163,074	162,413	163,067	162,203
Diluted (in shares)	166,263	164,768	165,976	164,226