Consolidated Statement of Stockholders' Equity (USD $)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earning [Member]	Treasury Stock [Member]	Total
Balances at Dec. 31, 2011	$ 6,531	$ 20,049,196	$ 0	$ (1,891,509)	$ 14,872,314
Balances (in shares) at Dec. 31, 2011	6,530,743
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock option plans	94	148,330	0	0	148,424
Issuance of common stock under stock option plans (in shares)	94,425
Stock compensation expense	0	228,485	0	0	228,485
Repurchases of common stock	0	0	0	(1,034,647)	(1,034,647)
Repurchases of common stock (in shares)	0
Excess tax benefits from share-based payment arrangements	0	262,695	0	0	262,695
Net income	0	0	2,981,075	0	2,981,075
Balances at Dec. 31, 2012	6,625	20,688,706	(310,929)	(2,926,156)	17,458,346
Balances (in shares) at Dec. 31, 2012	6,625,168
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock option plans	30	29,970	0	0	30,000
Issuance of common stock under stock option plans (in shares)	30,000
Effect of canceled of stock options	0	(75,928)	0	0	(75,928)
Effect of expiration of stock options (in shares)	0
Stock compensation expense	0	111,636	0	0	111,636
Repurchases of common stock	0	0	0	(674,874)	(674,874)
Repurchases of common stock (in shares)	0
Excess tax benefits from share-based payment arrangements	0	197,412	0	0	197,412
Net income	0	0	5,285,847	0	5,285,847
Balances at Dec. 31, 2013	6,655	20,951,796	4,975,018	(3,601,030)	22,332,439
Balances (in shares) at Dec. 31, 2013	6,655,168				6,354,429
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under stock option plans	407	2,146,414	0	0	2,146,821
Issuance of common stock under stock option plans (in shares)	407,042
Stock compensation expense	0	21,416	0	0	21,416
Repurchases of common stock	0	0	0	(829,613)	(829,613)
Repurchases of common stock (in shares)	0
Excess tax benefits from share-based payment arrangements	0	1,939,832	0	0	1,939,832
Net income	0	0	4,645,960	0	4,645,960
Balances at Dec. 31, 2014	$ 7,062	$ 25,059,458	$ 9,620,978	$ (4,430,643)	$ 30,256,855
Balances (in shares) at Dec. 31, 2014	7,062,209				6,730,622