Summary of Restricted Stock Unit Activity (Parenthetical) (Details) - shares
shares in Thousands
1 Months Ended 9 Months Ended
Jan. 31, 2016
Sep. 30, 2016
2013 RSUs    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Shares vested 128 202
RSUs Without Performance Conditions    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Shares vested   49