Stock Based Compensation - Outstanding stock options (Details) - Employee Stock Option	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Number of Shares
Options outstanding at beginning of period, shares | shares	16,680
Exercised, shares | shares	(1,500)
Options outstanding at end of period, shares | shares	15,180
Options exercisable at end of period, shares | shares	15,180
Weighted Average Exercise Price
Options outstanding at beginning of period (usd per share) | $ / shares	$ 16.30
Exercised (usd per share) | $ / shares	11.00
Options outstanding at end of period (usd per share) | $ / shares	16.82
Options exercisable at end of period (usd per share) | $ / shares	$ 16.82