Consolidated Statement of Stockholders' Equity - USD ($)	Total	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Class A Common Stock [Member]	Class B Common Stock [Member]
Beginning balance at Dec. 31, 2018	$ 398,869,901	$ 261,258,423	$ (14,228,059)	$ 192,751,208	$ (41,226,357)	$ 258,194	$ 56,492
Beginning balance, shares at Dec. 31, 2018						25,819,341	5,649,240
Issuance of common stock (stock compensation plans)	404,055	403,722				$ 333
Issuance of common stock (stock compensation plans), shares						33,334
Share-based compensation	442,920	442,920
Net income	23,023,164			23,023,164
Cash dividends declared	(4,752)			(4,752)
Grant of stock options		144,226		(144,226)
Other comprehensive income	6,468,473		6,468,473
Ending balance at Mar. 31, 2019	429,203,761	262,249,291	(7,759,586)	215,625,394	(41,226,357)	$ 258,527	$ 56,492
Ending balance, shares at Mar. 31, 2019						25,852,675	5,649,240
Beginning balance at Dec. 31, 2019	451,015,519	268,151,601	504,170	223,267,573	(41,226,357)	$ 262,040	$ 56,492
Beginning balance, shares at Dec. 31, 2019						26,203,935	5,649,240
Issuance of common stock (stock compensation plans)	376,828	376,539				$ 289
Issuance of common stock (stock compensation plans), shares						28,924
Share-based compensation	1,242,986	1,242,315				$ 671
Share-based compensation, shares						67,087
Net income	3,731,121			3,731,121
Cash dividends declared	(5,363)			(5,363)
Grant of stock options		118,525		(118,525)
Other comprehensive income	3,199,840		3,199,840
Ending balance at Mar. 31, 2020	$ 459,560,931	$ 269,888,980	$ 3,704,010	$ 226,874,806	$ (41,226,357)	$ 263,000	$ 56,492
Ending balance, shares at Mar. 31, 2020						26,299,946	5,649,240