Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation - Activity (Details)

v3.6.0.2
Share-Based Compensation - Activity (Details) - USD ($)
12 Months Ended
Feb. 22, 2016
Dec. 31, 2016
Dec. 31, 2015
Unrecognized share-based compensation expense      
Restricted stock awards, Unrecognized compensation expense   $ 11,670,000  
Restricted stock awards, Weighted average remaining vesting period   1 year 7 months 6 days  
Stock options, Unrecognized compensation expense   $ 4,629,000  
Stock options, Weighted average remaining vesting period   1 year 7 months 6 days  
Total unrecognized compensation expense related to unvested awards   $ 16,299,000  
Restricted stock awards, additional disclosures      
Grant date fair value $ 2,129,000    
Restricted Stock Awards      
Restricted Stock Awards, Number of Shares      
Balance at beginning of period (in shares)   586,600  
Replacement awards (in shares)   347,300  
Vested (in shares)   (216,100)  
Forfeited (in shares)   (64,700)  
Balance at end of period (in shares)   653,100 586,600
Restricted Stock Awards, Weighted Average Grant Date Fair Value Per Share      
Balance at beginning of period (in dollars per share)   $ 21.97  
Replacement awards (in dollars per share)   29.03  
Vested (in dollars per share)   21.12  
Forfeited (in dollars per share)   24.91  
Balance at end of period (in dollars per share)   $ 25.71 $ 21.97
Assumptions used to estimate the fair values of the awards granted:      
Remaining measurement period   2 years 10 months 10 days  
Risk free interest rate (as a percent)   0.90%  
Dividend yield (as a percent)   0.00%  
Estimated fair value of awards granted (in dollars per share)   $ 33.77  
Stock Options      
Stock Options, Number of Shares      
Balance at beginning of period (in shares)   387,600  
Replacement awards (in shares)   409,300  
Exercised (in shares)   (16,100)  
Forfeited (in shares)   (68,800)  
Balance at end of period (in shares)   712,000 387,600
Stock Options, Weighted Average Grant Date Fair Value Per Share      
Balance at beginning of period (in dollars per share)   $ 9.35  
Replacement awards (in dollars per share)   10.20  
Vested (in dollars per share)   10.34  
Forfeited (in dollars per share)   10.28  
Balance at end of period (in dollars per share)   9.73 $ 9.35
Stock Options, Weighted Average Exercise Price Per Share      
Balance at beginning of period (in dollars per share)   24.03  
Replacement awards (in dollars per share)   26.30  
Exercised (in dollars per share)   26.75  
Forfeited (in dollars per share)   26.56  
Balance at end of period (in dollars per share)   $ 25.03 $ 24.03
Stock options, additional disclosures      
Aggregate intrinsic value   $ 7,525,800 $ 2,611,700
Converted/Exercised aggregate intrinsic value   $ 156,200  
Exercisable, Number of shares   108,100  
Exercisable, Weighted Average Grant Date Fair Value Per Share   $ 7.95  
Exercisable Weighted Average Exercise Price Per Share   $ 20.31  
Exercisable, Aggregate Intrinsic Value   $ 1,653,600  
Weighted average remaining contractual term for vested but unexercised stock options   6 years 4 months 24 days  
Assumptions used to estimate the fair values of the awards granted:      
Risk free interest rate (as a percent)   1.51% 1.82%
Expected volatility using historical return volatility and implied volatility (as a percent)   38.00% 37.00%
Expected life (in years)   6 years 6 years
Dividend yield (as a percent)   0.00% 0.00%
Weighted-average estimated fair value of options granted during the year (in dollars per share)   $ 10.20 $ 10.44
Performance-based conditions | Restricted Stock Awards | Payout Range-0%      
Restricted stock awards, additional disclosures      
Related expenses $ 0    
Performance-based conditions | Restricted Stock Awards | Payout Range-25%      
Restricted stock awards, additional disclosures      
Payout range (as a percent) 25.00%    
Related expenses $ 532,000    
Performance-based conditions | Restricted Stock Awards | Payout Range-100%      
Restricted stock awards, additional disclosures      
Payout range (as a percent) 100.00%    
Related expenses $ 2,129,000    
Performance-based conditions | Restricted Stock Awards | Payout Range-200%      
Restricted stock awards, additional disclosures      
Payout range (as a percent) 200.00%    
Related expenses $ 4,258,000