Intangible Assets and Goodwill (Details) (USD $) In Thousands, unless otherwise specified													9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Customer relationships [Member]	Dec. 31, 2011 Customer relationships [Member]	Sep. 30, 2012 Acquired technology [Member]	Dec. 31, 2011 Acquired technology [Member]	Sep. 30, 2012 Non-compete agreements [Member]	Dec. 31, 2011 Non-compete agreements [Member]	Sep. 30, 2012 Trademarks [Member]	Dec. 31, 2011 Trademarks [Member]	Sep. 30, 2012 Domain names [Member]	Dec. 31, 2011 Domain names [Member]	Sep. 30, 2012 Maximum [Member] Customer relationships [Member]	Sep. 30, 2012 Maximum [Member] Acquired technology [Member]	Sep. 30, 2012 Maximum [Member] Non-compete agreements [Member]	Sep. 30, 2012 Minimum [Member] Customer relationships [Member]	Sep. 30, 2012 Minimum [Member] Acquired technology [Member]	Sep. 30, 2012 Minimum [Member] Non-compete agreements [Member]
Schedule of components of intangible assets
Intangible Assets Useful Life													15 years	15 years	6 years	7 years	8 years	3 years
Customer relationships, Gross Carrying Amount			$ 56,448	$ 49,222
Acquired technology, Gross Carrying Amount					50,763	39,742
Non-compete agreements, Gross Carrying Amount							11,984	11,995
Trademarks/Domain names, Gross Carrying Amount									33,577	30,028	4,400	4,400
Total, Gross Carrying Amount	157,172	135,387
Accumulated Amortization	(70,709)	(63,723)	(35,015)	(31,080)	(23,998)	(21,038)	(11,696)	(11,605)
Net Balance			21,433	18,142	26,765	18,704	288	390
Net Balance									33,577	30,028	4,400	4,400
Total	$ 86,463	$ 71,664