Stock Compensation Plans - Options Granted and Intrinsic Value (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Stock Compensation Plans
Options granted	208,400	202,700	196,350
The total intrinsic value of options exercised	$ 2,600,000	$ 1,400,000	$ 371,000
Proceeds from Stock Options Exercised	6,258,000	3,700,000	661,000
The actual tax benefit realized for the tax deductions from option exercises	2,300,000	1,200,000	257,000
The total intrinsic value of options outstanding	6,700,000	9,200,000	4,500,000
The total intrinsic value of options exercisable	$ 4,100,000	$ 5,300,000	$ 2,900,000