Summary of Significant Accounting Policies - Calculation Of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Standards Update and Change in Accounting Principle [Abstract]
Net income	$ 37,517	$ 32,888	$ 20,691
Basic weighted average common shares outstanding (in shares)	6,180,801	6,354,687	6,708,622
Dilutive effect of potential common shares from awards granted under equity incentive program (in shares)	68,000	76,000	99,000
Total (in shares)	6,249,313	6,431,367	6,808,209
Earnings per common share
Basic (in USD per share)	$ 6.07	$ 5.18	$ 3.08
Diluted (in USD per share)	$ 6.00	$ 5.11	$ 3.04