Stock-Based Compensation - Activity of stock incentive plans for options (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Option Shares Outstanding
Forfeited (in shares)	(16,671)
Stock Incentive Plan | Stock Options
Option Shares Outstanding
Beginning balance outstanding (in shares)	1,443,733
Granted (in shares)	39,500
Exercise of stock options (in shares)	(38,702)
Forfeited (in shares)	0
Ending balance outstanding (in shares)	1,444,531
Exercisable (in shares)	554,331
Weighted Average Exercise Price
Beginning balance outstanding (in usd per share) | $ / shares	$ 48.75
Granted (in usd per share) | $ / shares	71.89
Exercise of stock options (in usd per share) | $ / shares	23.83
Forfeited (in usd per share) | $ / shares	0.00
Ending balance outstanding (in usd per share) | $ / shares	50.06
Exercisable (in usd per share) | $ / shares	$ 43.43
Weighted average remaining life outstanding (in years)	7 years 3 months 14 days
Weighted average remaining life exercisable (in years)	6 years 6 months 18 days
Aggregate intrinsic value outstanding | $	$ 10,543
Aggregate intrinsic value exercisable | $	$ 6,293