Employee Benefit Plans - Restricted Stock Activity (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Employee Benefit Plans      
Compensation cost $ 9,000 $ 7,500 $ 3,600
Restricted stock      
Employee Benefit Plans      
Compensation cost 88 118 84
Unrecognized compensation cost $ 43 $ 132 $ 265
Period for recognition 3 years    
Shares      
Unvested restricted stock, beginning balance (in shares) 204,444    
Vested (in shares) (191,111)    
Unvested restricted stock, end balance (in shares) 13,333 204,444  
Aggregate Intrinsic Value      
Unvested restricted stock aggregate intrinsic value $ 16    
Restricted stock | Minimum      
Employee Benefit Plans      
Vesting period 1 year    
Restricted stock | Maximum      
Employee Benefit Plans      
Vesting period 3 years