Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation - Summary of Restricted Stock Awards and Units (Details)

v3.7.0.1
Stock Based Compensation - Summary of Restricted Stock Awards and Units (Details) - $ / shares
3 Months Ended 12 Months Ended
Mar. 31, 2017
Dec. 31, 2016
2010 Plan    
Stock-based compensation    
Maximum number of shares of common stock that may be issued 2,130,000  
Performance Share Unit Awards | 2010 Plan    
Weighted Average Grant Date Fair Value    
Granted (in dollars per share) $ 33.60  
Restricted Stock Unit Awards    
Shares    
Unvested at the beginning of the period (in shares) 47,790  
Granted (in shares) 127,420  
Vested (in shares) (123,239)  
Unvested at the end of the period (in shares) 51,971 47,790
Expected to vest in the future, at the end of the period (in shares) 51,971  
Weighted Average Grant Date Fair Value    
Unvested at the beginning of the period (in dollars per share) $ 20.31  
Granted (in dollars per share) 24.13  
Vested (in dollars per share) 22.94  
Cancelled and forfeited (in dollars per share) 0.00  
Unvested at the end of the period (in dollars per share) 23.45 $ 20.31
Expected to vest in the future, at the end of the period (in dollars per share) $ 23.45  
Weighted Average Remaining Contractual Term    
Unvested at the beginning of the period 1 year 4 months 6 days 11 months 16 days
Granted 5 months 23 days  
Unvested at the end of the period 1 year 4 months 6 days 11 months 16 days
Expected to vest in future, at the end of the period 1 year 4 months 6 days