Property and Equipment - Depreciation and Software Amortization Expense (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended 9 Months Ended
Sep. 30, 2012
Jun. 30, 2011
Jun. 30, 2011
Sep. 30, 2012
Depreciation and Amortization Expenses [Line Items]        
Depreciation $ 4,832 $ 5,303 $ 15,892 $ 14,624
Service costs [Member]
       
Depreciation and Amortization Expenses [Line Items]        
Depreciation 3,587 4,112 12,305 10,789
Sales and marketing [Member]
       
Depreciation and Amortization Expenses [Line Items]        
Depreciation 105 109 296 345
Product development [Member]
       
Depreciation and Amortization Expenses [Line Items]        
Depreciation 234 399 1,158 787
General and administrative [Member]
       
Depreciation and Amortization Expenses [Line Items]        
Depreciation $ 906 $ 683 $ 2,133 $ 2,703