Statements of changes in Stockholders' Equity (Deficit) - USD ($)	Common Stock Common Class A	Common Stock Common Class C	Additional Paid-in Capital	AOCI Attributable to Parent	Retained Earnings	Treasury Stock	Total
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2017	$ 29,071,154	$ 4,178,748	$ 38,125,042	$ 603,170	$ 77,520,951	$ (931,075)	$ 148,567,990
Cumulative effect adjustment upon adoption of new accounting standard (ASU 2016-01)	0	0	0	(603,170)	603,170	0	0
Net earnings	0	0	0	0	21,686,079	0	21,686,079
Other comprehensive income (loss), net of income tax	0	0	0	(2,823)	0	0	(2,823)
Share-based Payment Arrangement, Amount Capitalized	0	0	237,123	0	0	0	237,123
Exercise of stock options	76,946	0	(19,534)	0	0	0	57,412
Benefit plans funded with treasury stock	0	0	540,713	0	0	940,200	1,480,913
Payments to acquire treasury stock	0	0	0	0	0	(215,521)	(215,521)
Stock dividends	1,461,120	208,914	2,938,434	0	(4,608,468)	0	0
Conversion Class C to Class A	376	(376)	0	0	0	0	0
Stockholders' Equity Attributable to Parent, Ending Balance at Dec. 31, 2018	30,609,596	4,387,286	41,821,778	(2,823)	95,201,732	(206,396)	171,811,173
Net earnings	0	0	0	0	10,893,519	0	10,893,519
Other comprehensive income (loss), net of income tax	0	0	0	13,729,337	0	0	13,729,337
Share-based Payment Arrangement, Amount Capitalized	0	0	256,996	0	0	0	256,996
Exercise of stock options	65,034	382,886	415,990	0	0	0	863,910
Benefit plans funded with treasury stock	0	0	529,858	0	0	165,702	695,560
Payments to acquire treasury stock	0	0	0	0	0	(1,539,888)	(1,539,888)
Stock dividends	1,534,356	238,174	3,066,490	0	(4,839,022)	0	(2)
Conversion Class C to Class A	6,572	(6,572)	0	0	0	0	0
Stockholders' Equity Attributable to Parent, Ending Balance at Dec. 31, 2019	$ 32,215,558	$ 5,001,774	$ 46,091,112	$ 13,726,514	$ 101,256,229	$ (1,580,582)	$ 196,710,605