Consolidated Statements Of Cash Flows (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended				0 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Engage [Member]	Jun. 13, 2012 LookIO [Member]	Dec. 31, 2012 LookIO [Member]
Supplemental disclosure of non-cash investing activities:
Capitalized equipment related to the Company's co-location facility	$ 745	$ 1,631	$ 1,259
Net cash paid for income taxes	1,556	2,579	3,800
Shares issued In connection with acquisition of Look.io, Shares					109,517	139,939
Shares issued In connection with acquisition of Look.io, Value					1,984
Potential shares of common stock in addition to purchase price					30,422	30,422
Share-based compensation	10,715	6,771	5,142		149
Costs related to earn out litigation	77	75	95
Costs related to earn out				$ 1,660