Condensed Consolidated Statements Of Operations and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Statement [Abstract]
Revenues	$ 223,528	$ 196,965	$ 643,396	$ 568,332
Costs and expenses:
Cost of revenues	41,460	41,694	125,560	123,230
Sales and marketing	22,928	25,090	77,056	69,660
Research and development	15,409	13,488	45,635	40,156
General and administrative	27,669	24,775	73,903	86,610
Restructuring charges	0	2,971	(730)	12,160
Total costs and expenses	107,466	108,018	321,424	331,816
Operating income	116,062	88,947	321,972	236,516
Interest expense	(12,619)	(11,797)	(37,539)	(135,473)
Non-operating (loss) income, net	(1,742)	3,591	(3,032)	15,218
Income from continuing operations before income taxes	101,701	80,741	281,401	116,261
Income tax expense	(24,882)	(22,126)	(70,005)	(23,034)
Income from continuing operations, net of tax	76,819	58,615	211,396	93,227
Income (loss) from discontinued operations, net of tax	1,091	301	2,995	(4,150)
Net income	77,910	58,916	214,391	89,077
Foreign currency translation adjustments	0	(78)	0	(2)
Change in unrealized gain on investments, net of tax	2,499	94	2,536	703
Realized gain on investments, net of tax, included in net income	(20)	(1,136)	(55)	(2,551)
Other comprehensive income (loss)	2,479	(1,120)	2,481	(1,850)
Comprehensive income	$ 80,389	$ 57,796	$ 216,872	$ 87,227
Basic income (loss) per share
Continuing operations	$ 0.49	$ 0.36	$ 1.34	$ 0.56
Discontinued operations	$ 0.01	$ 0.00	$ 0.02	$ (0.03)
Net income	$ 0.50	$ 0.36	$ 1.36	$ 0.53
Diluted income (loss) per share
Continuing operations	$ 0.46	$ 0.36	$ 1.28	$ 0.55
Discontinued operations	$ 0.01	$ 0.00	$ 0.02	$ (0.02)
Net income	$ 0.47	$ 0.36	$ 1.30	$ 0.53
Shares used to compute net income per share
Basic	156,261	163,046	157,729	167,492
Diluted	166,575	163,902	164,540	169,176