v3.21.1
Stock incentive plans - Stock option awards (Details) - Stock options - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended
Dec. 31, 2020
Mar. 31, 2021
Number of Options    
Outstanding at beginning of period (in shares)   109
Exercised (in shares)   (13)
Outstanding and exercisable at end of period (in shares) 109 96
Weighted Average Exercise Price    
Outstanding at beginning of period (in dollars per share)   $ 7.75
Exercised (in dollars per share)   9.64
Outstanding and exercisable at end of period (in dollars per share) $ 7.75 $ 7.48
Weighted-Average Remaining Contract Life (years)    
Outstanding and exercisable at end of period 1 year 9 months 18 days 1 year 8 months 12 days
Aggregate Intrinsic Value    
Outstanding and exercisable at end of period $ 559 $ 630