Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenues	$ 1,327,576	$ 1,265,052	$ 1,231,661
Costs and expenses:
Cost of revenues	191,933	180,177	180,467
Sales and marketing	39,877	36,790	46,637
Research and development	80,529	74,671	60,805
General and administrative	148,434	149,213	137,625
Total costs and expenses	460,773	440,851	425,534
Operating income	866,803	824,201	806,127
Interest expense	(83,255)	(90,144)	(90,611)
Non-operating income, net	(1,329)	16,187	43,260
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest, Total	782,219	750,244	758,776
Income tax (expense) benefit	2,611	64,644	(146,477)
Net income	784,830	814,888	612,299
Other Comprehensive Income (Loss), Net of Tax	(29)	(135)	190
Comprehensive income	$ 784,801	$ 814,753	$ 612,489
Earnings per share
Earnings Per Share, Basic	$ 7.01	$ 7.08	$ 5.17
Earnings Per Share, Diluted	$ 7.00	$ 7.07	$ 5.15
Shares used to compute net income per share
Basic	112,015	115,058	118,513
Diluted	112,166	115,298	118,968