Income and Dividends Per Share of Common Stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income per share of common stock:
Net income for basic and diluted income per common share	$ 17,104	$ 8,668
Weighted-average shares for basic income per common share (in shares)	5,685	5,667
Effect of dilutive securities:
Employee and director stock options (in shares)	13	10
Adjusted weighted-average shares and assumed exercises for diluted income per common share (in shares)	5,698	5,677
Basic net income per common share (in dollars per share)	$ 3.01	$ 1.53
Diluted net income per common share (in dollars per share)	3.00	1.53
Cash dividends per share of common stock (in dollars per share)	$ 0.20	$ 0.20
Options
Anti-dilutive securities
Anti-dilutive shares of common stock excluded from the calculation of dilutive securities	0	7