Condensed Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues	$ 334,242	$ 317,879	$ 987,268	$ 944,768
Costs and expenses:
Cost of revenues	47,801	45,024	142,565	134,205
Sales and marketing	9,410	8,389	28,115	23,883
Research and development	19,566	19,708	59,685	55,268
General and administrative	36,160	38,109	112,212	111,719
Total costs and expenses	112,937	111,230	342,577	325,075
Operating income	221,305	206,649	644,691	619,693
Interest expense	(18,829)	(22,537)	(64,427)	(67,607)
Non-operating income (loss), net	164	775	(1,433)	15,262
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest, Total	202,640	184,887	578,831	567,348
Income tax expense	(46,018)	(13,908)	(124,083)	90,226
Net Income	156,622	170,979	454,748	657,574
Other comprehensive income (loss)	61	(383)	(17)	(120)
Comprehensive Income	$ 156,683	$ 170,596	$ 454,731	$ 657,454
Basic income (loss) per share
Net Income	$ 1.40	$ 1.49	$ 4.05	$ 5.70
Diluted income (loss) per share
Net Income	$ 1.40	$ 1.49	$ 4.04	$ 5.68
Shares used to compute net income per share
Basic	111,664	114,655	112,389	115,456
Diluted	111,793	114,831	112,530	115,699