Condensed Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues	$ 314,365	$ 306,289	$ 626,889	$ 612,697
Costs and expenses:
Cost of revenues	43,608	44,066	89,181	89,570
Sales and marketing	8,890	12,399	15,494	22,918
Research and development	18,202	14,953	35,560	31,085
General and administrative	36,885	33,178	73,610	67,179
Total costs and expenses	107,585	104,596	213,845	210,752
Operating income	206,780	201,693	413,044	401,945
Interest expense	(22,535)	(22,635)	(45,070)	(45,266)
Non-operating income (loss), net	7,403	11,436	14,487	23,639
Income before income taxes	191,648	190,494	382,461	380,318
Income tax expense	(39,169)	(42,960)	104,134	(70,257)
Net Income	152,479	147,534	486,595	310,061
Other comprehensive income (loss)	(2,000)	35	263	84
Comprehensive Income	$ 150,479	$ 147,569	$ 486,858	$ 310,145
Basic income (loss) per share
Net Income	$ 1.32	$ 1.24	$ 4.20	$ 2.60
Diluted income (loss) per share
Net Income	$ 1.32	$ 1.24	$ 4.19	$ 2.59
Shares used to compute net income per share
Basic	115,347	118,965	115,861	119,359
Diluted	115,544	119,361	116,137	119,837