Stock Options (Details) - USD ($)		3 Months Ended		9 Months Ended
	Apr. 18, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Apr. 05, 2012
Employee Stock Options
Stock Options, Aggregate intrinsic value
Stock-based compensation expense		$ 118,000	$ 118,000	$ 347,000	$ 391,000
Employee Stock Options | 2012 Plan
Stock option details
Shares available for future grants						800,000
Maximum exercisable period for granted share-based compensation				10 years
Number of options granted (in shares)				31,150
Stock option activity
Options outstanding at the beginning of the period (in shares)				520,551
Plus: Options granted (in shares)				31,150
Less:
Exercise of stock options (in shares)				34,025
Options forfeited (in shares)				12,400
Options outstanding at the end of the period (in shares)		505,276		505,276
Options fully vested and exercisable at the end of the period (in shares)		293,638		293,638
Stock Options, Weighted average exercise price
Options outstanding at the beginning, weighted average exercise price (in dollars per share)				$ 28.28
Plus: Options granted, weighted average exercise price (in dollars per share)				38.92
Less:
Options exercised, weighted average exercise price (in dollars per share)				21.54
Options forfeited, weighted average exercise price (in dollars per share)				32.64
Options outstanding at the end, weighted average exercise price (in dollars per share)		$ 29.29		29.29
Options fully vested and exercisable at the end, weighted average exercise price (in dollars per share)		$ 24.93		$ 24.93
Stock Options, Weighted average remaining contractual term (years)
Options outstanding at the end, weighted average remaining contractual term (years)				4 years 2 months 12 days
Options fully vested and exercisable at the end, weighted average remaining contractual term (years)				2 years 5 months 4 days
Stock Options, Aggregate intrinsic value
Options outstanding at the end, aggregate intrinsic value		$ 6,677,000		$ 6,677,000
Options fully vested and exercisable at the end, aggregate intrinsic value		5,160,000		5,160,000
Stock-based compensation cost, unrecognized, related to non-vested options		$ 863,000		$ 863,000
Stock-based compensation cost, unrecognized, related to non-vested options, weighted-average period of recognition				1 year 8 months 12 days
Stock Appreciation Rights | SAR Plan
Stock option details
Shares available for future grants	750,000
Maximum exercisable period for granted share-based compensation	10 years	10 years
Number of rights issued		500,250
Base value of units issued (per unit)		$ 39.33
Vesting period	8 years	8 years
Incentive Stock Options to 10 Percent Shareholders | 2012 Plan
Stock option details
Maximum exercisable period for granted share-based compensation				5 years