CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2017	$ 44,145	$ 19,865,273	$ 20,807,679	$ 40,717,097
Balance, shares at Dec. 31, 2017	4,414,492
Exercise of stock options	$ 555	485,989		486,544
Exercise of stock options, shares	55,500
Stock-based compensation		268,816		268,816
Dividend distribution			(941,006)	(941,006)
401(K) stock match	$ 250	404,075		404,325
401(K) stock match, shares	24,992
Issuance of deferred stock awards	$ 28	28		56
Issuance of deferred stock awards, shares	2,788
Shares issued under Employee Stock Purchase Plan	$ 86	113,496		113,582
Shares issued under Employee Stock Purchase Plan, shares	8,582
Net income			3,347,890	3,347,890
Balance at Sep. 30, 2018	$ 45,064	21,137,677	23,214,563	44,397,304
Balance, shares at Sep. 30, 2018	4,506,354
Balance at Jun. 30, 2018	$ 44,826	20,816,671	21,897,162	42,758,659
Balance, shares at Jun. 30, 2018	4,482,567
Exercise of stock options	$ 110	71,383		71,493
Exercise of stock options, shares	10,975
Stock-based compensation		64,950		64,950
Dividend distribution			(315,444)	(315,444)
401(K) stock match	$ 83	127,122		127,205
401(K) stock match, shares	8,284
Shares issued under Employee Stock Purchase Plan	$ 45	57,551		57,596
Shares issued under Employee Stock Purchase Plan, shares	4,528
Net income			1,632,845	1,632,845
Balance at Sep. 30, 2018	$ 45,064	21,137,677	23,214,563	44,397,304
Balance, shares at Sep. 30, 2018	4,506,354
Balance at Dec. 31, 2018	$ 45,277	21,420,886	25,268,187	46,734,350
Balance, shares at Dec. 31, 2018	4,527,685
Exercise of stock options	$ 328	206,264		206,592
Exercise of stock options, shares	32,810
Other share retirements	$ (59)	(27,915)	(62,023)	(89,997)
Other share retirements, shares	(5,863)
Stock-based compensation		203,333		203,333
Dividend distribution			(964,242)	(964,242)
401(K) stock match	$ 424	567,994		568,418
401(K) stock match, shares	42,405
Issuance of deferred stock awards	$ 110	(55,044)		(54,934)
Issuance of deferred stock awards, shares	10,968
Shares issued under Employee Stock Purchase Plan	$ 114	127,217		127,331
Shares issued under Employee Stock Purchase Plan, shares	11,416
Net income			2,164,832	2,164,832
Balance at Sep. 30, 2019	$ 46,194	22,442,735	26,406,754	48,895,683
Balance, shares at Sep. 30, 2019	4,619,421
Balance at Jun. 30, 2019	$ 46,041	22,223,470	25,579,114	47,848,625
Balance, shares at Jun. 30, 2019	4,604,107
Exercise of stock options	$ 25	20,675		20,700
Exercise of stock options, shares	2,500
Stock-based compensation		39,825		39,825
Dividend distribution			(322,845)	(322,845)
401(K) stock match	$ 128	158,765		158,893
401(K) stock match, shares	12,814
Net income			1,150,485	1,150,485
Balance at Sep. 30, 2019	$ 46,194	$ 22,442,735	$ 26,406,754	$ 48,895,683
Balance, shares at Sep. 30, 2019	4,619,421