Consolidated Statements of Income (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Income Statement [Abstract]
Revenues	$ 218,255	$ 158,095	$ 326,292	$ 320,238
Costs of revenues	141,311	98,734	213,338	204,917
Gross profit	76,944	59,361	112,954	115,321
Product development	255	422	423	607
Selling, general and administrative expenses	29,554	27,751	59,683	51,261
Operating income	47,135	31,188	52,848	63,453
Interest income, net	44	171	260	230
Other income, net	2,060	2,004	4,060	4,097
Decrease (increase) in income tax benefit payable to former stockholder	175	(8,668)	4,764	(16,856)
Income before income taxes	49,414	24,695	61,932	50,924
Provision for income taxes	15,341	720	19,065	5,280
Net income	$ 34,073	$ 23,975	$ 42,867	$ 45,644
Basic net income per share	$ 0.41	$ 0.28	$ 0.51	$ 0.53
Diluted net income per share	$ 0.40	$ 0.27	$ 0.51	$ 0.51
Shares used in computing net income per share
Basic	83,384	85,709	83,759	86,741
Diluted	84,565	87,582	84,854	88,972