Condensed Consolidated Statements Of Comprehensive 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
Revenues	$ 317,879	$ 308,421	$ 944,768	$ 921,118
Costs and expenses:
Cost of revenues	45,024	44,443	134,205	134,013
Sales and marketing	8,389	9,857	23,883	32,775
Research and development	19,708	14,619	55,268	45,704
General and administrative	38,109	33,886	111,719	101,065
Total costs and expenses	111,230	102,805	325,075	313,557
Operating income	206,649	205,616	619,693	607,561
Interest expense	(22,537)	(22,633)	(67,607)	(67,899)
Non-operating income (loss), net	775	10,498	15,262	34,137
Income before income taxes	184,887	193,481	567,348	573,799
Income tax expense	(13,908)	(39,568)	90,226	(109,825)
Net Income	170,979	153,913	657,574	463,974
Other comprehensive income (loss)	(383)	308	(120)	392
Comprehensive Income	$ 170,596	$ 154,221	$ 657,454	$ 464,366
Basic income (loss) per share
Net Income	$ 1.49	$ 1.30	$ 5.70	$ 3.90
Diluted income (loss) per share
Net Income	$ 1.49	$ 1.30	$ 5.68	$ 3.89
Shares used to compute net income per share
Basic	114,655	118,194	115,456	118,966
Diluted	114,831	118,569	115,699	119,410