Summary of Significant Accounting Policies - Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Anti-dilutive securities
Net Income (Loss)	$ 74,549	$ 45,429	$ 37,045
Weighted-average shares for basic income per common share (in shares)	5,692,391	5,671,960	5,656,367
Effect of dilutive securities:
Employee and director stock options (in shares)	14,285	8,449	11,992
Adjusted weighted-average shares and assumed exercises for diluted income per common share (in shares)	5,706,676	5,680,409	5,668,359
Basic net income per common share (in dollars per share)	$ 13.10	$ 8.01	$ 6.55
Diluted net income per common share (in dollars per share)	13.06	8.00	6.54
Cash dividends per share of common stock (in dollars per share)	$ 0.80	$ 0.80	$ 0.64
Options
Effect of dilutive securities:
Anti-dilutive shares of common stock excluded from the calculation of dilutive securities	1,875	16,125	600