Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($)	Common Stock [Member] Common Class A [Member]	Common Stock [Member] Common Class C [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Treasury Stock, Common [Member]	Total
Beginning balance, value at Dec. 31, 2021	$ 35,285,444	$ 5,733,130	$ 57,985,947	$ 18,070,448	$ 184,537,489	$ (1,845,624)	$ 299,766,834
Net earnings					3,228,718		3,228,718
Other comprehensive gain (loss)				(12,190,330)			(12,190,330)
Stock-based compensation expense			271,747				271,747
Exercise of stock options	100,446		(8,487)				91,959
Sale of treasury stock			24,055			1,880,125	1,904,180
Purchase of treasury stock			106,176			(878,417)	(772,241)
Conversion Class C to Class A	414	(414)
Ending balance, value at Mar. 31, 2022	35,386,304	5,732,716	58,379,438	5,880,118	187,766,207	(843,916)	292,300,867
Beginning balance, value at Dec. 31, 2022	37,516,062	5,779,718	64,767,769	(13,070,277)	202,160,306	(4,366,651)	292,786,927
Cumulative effect adjustment upon adoption of new accounting standard (ASU 2016-13)					(671,506)		(671,506)
Net earnings					1,240,172		1,240,172
Other comprehensive gain (loss)				4,127,558			4,127,558
Stock-based compensation expense			143,671				143,671
Exercise of stock options	96,092		(62,073)				34,019
Sale of treasury stock			(43,493)			620,651	577,158
Purchase of treasury stock						(1,204,357)	(1,204,357)
Conversion Class C to Class A	1,872	(1,872)
Ending balance, value at Mar. 31, 2023	$ 37,614,026	$ 5,777,846	$ 64,805,874	$ (8,942,719)	$ 202,728,972	$ (4,950,357)	$ 297,033,642