XML 63 R76.htm IDEA: XBRL DOCUMENT v3.20.1
Share-based compensation - Summary of changes in share based compensation (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Restricted stock units    
Restricted stock awards and restricted stock units    
Outstanding, beginning of period (in shares) 207,641 200,358
Granted (in shares) 77,679 94,559
Vested (in shares) (77,719) (76,712)
Forfeited (in shares) (4,160) (6,980)
Outstanding, end of period (in shares) 203,441 211,225
Weighted-average grant-date fair value per share    
Outstanding, beginning of period (in dollars per share) $ 35.36 $ 33.05
Granted (in dollars per share) 48.11 37.68
Vested (in dollars per share) 34.19 32.61
Forfeited (in dollars per share) 35.81 33.18
Outstanding, end of period (in dollars per share) $ 40.67 $ 35.28
Total weighted-average grant-date fair value $ 3.7 $ 3.6
LTIP linked to TRS    
Restricted stock awards and restricted stock units    
Outstanding, beginning of period (in shares) 96,402 65,578
Granted (in shares) 24,630 34,647
Vested (in shares) (29,409) 0
Forfeited (in shares) (1,007) (1,914)
Outstanding, end of period (in shares) 90,616 98,311
Weighted-average grant-date fair value per share    
Outstanding, beginning of period (in dollars per share) $ 39.62 $ 38.81
Granted (in dollars per share) 48.62 41.07
Vested (in dollars per share) 39.51 0
Forfeited (in dollars per share) 41.72 38.62
Outstanding, end of period (in dollars per share) $ 42.08 $ 39.61
Total weighted-average grant-date fair value $ 1.2 $ 1.4
LTIP awards linked to other performance conditions    
Restricted stock awards and restricted stock units    
Outstanding, beginning of period (in shares) 403,768 276,169
Granted (in shares) 98,522 138,580
Vested (in shares) (135,804) 0
Increase above target (in shares) (26,111) 0
Forfeited (in shares) (4,031) (7,659)
Outstanding, end of period (in shares) 336,344 407,090
Weighted-average grant-date fair value per share    
Outstanding, beginning of period (in dollars per share) $ 35.15 $ 33.80
Granted (in dollars per share) 48.10 37.68
Vested (in dollars per share) 33.48 0
Increase above target (in dollars per share) 34.13 0
Forfeited (in dollars per share) 39.67 33.91
Outstanding, end of period (in dollars per share) $ 39.64 $ 35.12
Total weighted-average grant-date fair value $ 4.7 $ 5.2