Income Taxes (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Dec. 31, 2014
Income Tax Contingency [Line Items]            
Income tax expense (benefit) $ 8,527 $ (22,075) $ (3,801) $ (27,784)    
Tax provision adjustment $ 800 $ 400        
Term of cumulative pretax net losses     3 years      
Term of improvement in book income     5 years      
FTC contempt action | Settled litigation            
Income Tax Contingency [Line Items]            
Settlement amount         $ 116,000  
Legal reserve            
Income Tax Contingency [Line Items]            
Reserves         $ 96,000 $ 20,000