Consolidated Balance Sheets Balance Sheet Parenthetical (USD $)
In Thousands, except Share data, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Allowance for doubtful accounts $ 1,063 $ 1,111
Preferred stock, par value (in USD per share) $ 0.0001 $ 0.0001
Preferred Stock, Shares Authorized 10,000,000 10,000,000
Preferred stock, shares issued 0 0
Preferred stock, shares outstanding 0 0
Common Class B [Member]    
Common stock, par value (in USD per share) $ 0.0001 $ 0.0001
Common Stock, shares authorized 75,000,000 75,000,000
Common Stock, shares issued 21,259,853 22,620,509
Common stock, shares outstanding 21,259,853 22,620,509
Common Class A [Member]    
Common stock, par value (in USD per share) $ 0.0001 $ 0.0001
Common Stock, shares authorized 750,000,000 750,000,000
Common Stock, shares issued 49,881,801 47,247,710
Common stock, shares outstanding 49,881,801 47,247,710