Condensed Consolidated Statements Of Operations and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Income Statement [Abstract]
Revenues	$ 205,726	$ 181,523
Costs and expenses:
Cost of revenues	41,256	40,869
Sales and marketing	27,815	22,391
Research and development	14,765	13,594
General and administrative	23,508	33,629
Restructuring charges	(548)	5,530
Total costs and expenses	106,796	116,013
Operating income	98,930	65,510
Interest expense	(12,340)	(11,820)
Non-operating income, net	807	5,478
Income from continuing operations before income taxes	87,397	59,168
Income tax expense	(21,292)	(16,875)
Income from continuing operations, net of tax	66,105	42,293
Income (loss) from discontinued operations, net of tax	1,904	(1,522)
Net income	68,009	40,771
Foreign currency translation adjustments	0	28
Change in unrealized gain on investments, net of tax	(5)	(458)
Realized gain on investments, net of tax, included in net income	(5)	(27)
Other comprehensive loss	(10)	(457)
Comprehensive income	$ 67,999	$ 40,314
Basic income (loss) per share
Continuing operations	$ 0.41	$ 0.25
Discontinued operations	$ 0.02	$ (0.01)
Net income	$ 0.43	$ 0.24
Diluted income (loss) per share
Continuing operations	$ 0.41	$ 0.25
Discontinued operations	$ 0.01	$ (0.01)
Net income	$ 0.42	$ 0.24
Shares used to compute net income per share
Basic	159,344	170,193
Diluted	162,881	171,979