Consolidated Statements Of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]
Revenues	$ 965,087	$ 873,592	$ 771,978
Costs and expenses:
Cost of revenues	187,013	167,600	165,246
Sales and marketing	89,337	97,809	97,432
Research and development	70,297	61,694	53,277
General and administrative	90,208	89,927	111,122
Restructuring charges	0	(765)	15,512
Total costs and expenses	436,855	416,265	442,589
Operating income	528,232	457,327	329,389
Interest expense	(74,761)	(50,196)	(147,332)
Non-operating income, net	3,300	5,564	11,530
Income from continuing operations before income taxes	456,771	412,695	193,587
Income tax expense	87,679	(100,210)	(55,031)
Income from continuing operations, net of tax	544,450	312,485	138,556
Income from discontinued operations, net of tax	0	7,547	4,335
Net income	544,450	320,032	142,891
Foreign currency translation adjustments	0	0	110
Realized foreign currency translation adjustments, included in net income	81	0	0
Change in unrealized gain on investments, net of tax	(369)	2,757	688
Realized gain on investments, net of tax, included in net income	(2,409)	(61)	(2,548)
Other comprehensive income (loss)	(2,697)	2,696	(1,750)
Comprehensive income	$ 541,753	$ 322,728	$ 141,141
Basic income per share
Continuing operations	$ 3.77	$ 1.99	$ 0.84
Discontinued operations	$ 0.00	$ 0.05	$ 0.03
Net income	$ 3.77	$ 2.04	$ 0.87
Diluted income per share
Continuing operations	$ 3.49	$ 1.91	$ 0.83
Discontinued operations	$ 0.00	$ 0.04	$ 0.03
Net income	$ 3.49	$ 1.95	$ 0.86
Shares used to compute net income per share
Basic	144,591	156,953	165,408
Diluted	155,786	163,909	166,887