Significant Accounting Policies - Additional Information (Details) (USD $)	3 Months Ended		12 Months Ended			3 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2012 Ziplist	Jun. 30, 2012 Pingg
Accounting Policies [Line Items]
Goodwill impairment	$ 44,300,000		$ 44,257,000	$ 0	$ 0
Definite-live intangible asset impairment charge		1,300,000		1,320,000
Proceeds from sale of investments						800,000	400,000
Realized gain on sale of investments						800,000	400,000
Securities excluded from computation of diluted earnings per share			5,883,719	7,345,060	5,389,222
Reclassified Operating Expenses					$ 4,000,000