Income and Dividends Per Share of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	May 02, 2024	Dec. 31, 2023
Anti-dilutive securities
Common stock, authorized shares	45,000,000						45,000,000		45,000,000	30,000,000
Common stock, shares outstanding	28,594,270						28,594,270			28,522,780
Income per share of common stock:
Net income for basic and diluted income per common share	$ 33,353	$ 26,057	$ 22,439	$ 20,733	$ 19,712	$ 17,104	$ 81,849	$ 57,549
Weighted-average shares for basic income per common share (in shares)	28,594,000			28,480,000			28,574,000	28,455,000
Effect of dilutive securities:
Employee and director stock options (in shares)	133,000			80,000			109,000	70,000
Adjusted weighted-average shares and assumed exercises for diluted income per common share (in shares)	28,727,000			28,560,000			28,683,000	28,525,000
Basic net income per common share (in dollars per share)	$ 1.17			$ 0.73			$ 2.86	$ 2.02
Diluted net income per common share (in dollars per share)	1.16			0.73			2.85	2.02
Cash dividends per share of common stock (in dollars per share)	$ 0.05			$ 0.04			$ 0.15	$ 0.12
Options
Anti-dilutive securities
Anti-dilutive shares of common stock excluded from the calculation of dilutive securities	0			0			0	0