Goodwill and Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Goodwill and Intangible Assets
Goodwill	$ 39,030		$ 39,030		$ 38,560
Accumulated impairment losses on goodwill	0		0		0
Intangible assets
Gross Amount	26,743		26,743		24,963
Accumulated Amortization	10,321		10,321		7,149
Indefinite-lived intangible assets	6,630		6,630		6,630
Total intangible assets	33,373		33,373		31,593
Amortization expense	1,110	500	3,172	1,294
Amortization expense for the next five years
2013 (remaining 3 months)	1,111		1,111
2014	4,145		4,145
2015	3,349		3,349
2016	2,301		2,301
2017	2,233		2,233
Trade names, trademarks and domain names
Intangible assets
Indefinite-lived intangible assets	6,630		6,630		6,630
Trade Names, Trademarks, Brand Names and Domain Names
Intangible assets
Gross Amount	1,530		1,530		530
Accumulated Amortization	607		607		521
Content Syndication Agreements
Intangible assets
Gross Amount	3,800		3,800		3,800
Accumulated Amortization	2,301		2,301		1,731
Purchased Technology
Intangible assets
Gross Amount	9,200		9,200		8,600
Accumulated Amortization	3,087		3,087		1,983
Customer Relationships
Intangible assets
Gross Amount	8,630		8,630		8,630
Accumulated Amortization	1,719		1,719		835
Other Intangible Assets Excluding Goodwill
Intangible assets
Gross Amount	3,583		3,583		3,403
Accumulated Amortization	$ 2,607		$ 2,607		$ 2,079