Geographic Data and Concentrations (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Dec. 31, 2011
Summary of revenue and long-lived assets          
Revenue $ 122,125 $ 98,449 $ 247,145 $ 197,527  
Long lived assets 991,869   991,869   982,827
USA [Member]
         
Summary of revenue and long-lived assets          
Revenue 120,210 96,488 243,403 193,358  
Long lived assets 987,199   987,199   978,010
International [Member]
         
Summary of revenue and long-lived assets          
Revenue 1,915 1,961 3,742 4,169  
Long lived assets 4,670   4,670   4,817
Online [Member]
         
Summary of revenue and long-lived assets          
Revenue 120,080 96,432 243,087 193,377  
Print [Member]
         
Summary of revenue and long-lived assets          
Revenue $ 2,045 $ 2,017 $ 4,058 $ 4,150