Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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+ Details

Goodwill and Intangible Assets (Changes in Carrying Amount of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Nov. 09, 2012	Sep. 30, 2013 Business [Member]	Dec. 31, 2012 Business [Member]	Sep. 30, 2013 Consumer [Member]	Dec. 31, 2012 Consumer [Member]	Dec. 31, 2011 Consumer [Member]	Dec. 31, 2012 Engage Pty Ltd. [Member]	Dec. 31, 2012 Engage Pty Ltd. [Member] Business [Member]	Dec. 31, 2012 Look.io [Member]	Jun. 13, 2012 Look.io [Member]	Dec. 31, 2012 Look.io [Member] Business [Member]
Goodwill [Roll Forward]
Beginning Balance	$ 32,645	$ 24,090		$ 24,621	$ 16,066	$ 8,024	$ 8,024	$ 8,024
Engage acquisition (see Note 8)	79			79
Goodwill			6,152						6,073	6,073	2,405	2,405	2,405
Contingent earnout payments (see Note 8)		77			77
Ending Balance	$ 32,724	$ 32,645		$ 24,700	$ 24,621	$ 8,024	$ 8,024	$ 8,024