Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Restricted Stock) (Details)

v3.19.2
Stock-Based Compensation (Restricted Stock) (Details)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2019
USD ($)
$ / shares
shares
Mar. 31, 2019
$ / shares
shares
Jun. 30, 2019
USD ($)
$ / shares
shares
Performance Shares      
Number of Shares      
Balance at the beginning of the period (in shares) | shares 188,794 124,320 124,320
Granted (in shares) | shares 123,812 68,510  
Vested (in shares) | shares (68,334) 0  
Forfeited (in shares) | shares 0 (4,036)  
Balance at the end of the period (in shares) | shares 244,272 188,794 244,272
Weighted-Average Grant Date Fair Value per Share      
Balance at the beginning of the period (in dollars per share) | $ / shares $ 51.42 $ 44.64 $ 44.64
Granted (in dollars per share) | $ / shares 73.60 64.32  
Vested (in dollars per share) | $ / shares 31.03 0  
Forfeited (in dollars per share) | $ / shares 0 61.27  
Balance at the end of the period (in dollars per share) | $ / shares $ 67.78 $ 51.42 $ 67.78
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]      
Vesting period     3 years
Unrecognized compensation expense related to shares | $ $ 17,371   $ 17,371
Unrecognized compensation expense weighted-average recognition period     2 years 8 months 12 days
Performance Shares | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]      
Number of shares to be vest upon each evaluation date, percentage 50.00%   50.00%
Performance Shares | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]      
Number of shares to be vest upon each evaluation date, percentage 150.00%   150.00%
Restricted Stock Units (RSUs)      
Number of Shares      
Balance at the beginning of the period (in shares) | shares 1,833,263 1,461,468 1,461,468
Granted (in shares) | shares 48,032 872,104  
Vested (in shares) | shares (114,056) (479,479)  
Forfeited (in shares) | shares (22,074) (20,830)  
Balance at the end of the period (in shares) | shares 1,745,165 1,833,263 1,745,165
Weighted-Average Grant Date Fair Value per Share      
Balance at the beginning of the period (in dollars per share) | $ / shares $ 53.67 $ 46.59 $ 46.59
Granted (in dollars per share) | $ / shares 68.50 60.94  
Vested (in dollars per share) | $ / shares 47.94 45.98  
Forfeited (in dollars per share) | $ / shares 56.55 48.31  
Balance at the end of the period (in dollars per share) | $ / shares $ 54.40 $ 53.67 $ 54.40
Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]      
Unrecognized compensation expense related to shares | $ $ 82,846   $ 82,846
Unrecognized compensation expense weighted-average recognition period     2 years 2 months 12 days