Stock Compensation Plans - Stock options activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, January 1, 2020 | shares	17,700
Option Outstanding, Forfeited or cancelled | shares	(1,500)
Option Outstanding, Exercised | shares	(19,922)
Option Outstanding, Exchanged | shares	39,983
Options outstanding, December 31, 2020 | shares	36,261
Exercisable at December 31, 2020 | shares	34,661
Weighted Average Exercise Price, Options outstanding, January 1, 2020 | $ / shares	$ 17.60
Weighted Average Exercise Price, Forfeited or cancelled | $ / shares	17.92
Weighted Average Exercise Price, Exercised | $ / shares	7.10
Weighted Average Exercise Price, Exchanged | $ / shares	16.00
Weighted Average Exercise Price, Options outstanding, December 31, 2020 | $ / shares	21.59
Weighted Average Exercise Price, Exercisable at December 31, 2020 | $ / shares	$ 21.72
Weighted Average Remaining Contractual Term (In years), outstanding, December 31, 2020	5 years 9 months 10 days
Weighted Average Remaining Contractual Terms (In years), Exercisable at December 31, 2020	5 years 9 months 21 days
Aggregate Intrinsic Value, outstanding, December 31, 2020 | $	$ 107
Aggregate Intrinsic Value, Exercisable at December 31, 2020 | $	$ 100