Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2014	$ 1,600	$ 14,780,100	$ 20,563,300	$ (504,100)	$ 34,840,900
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	6,437,600	0	6,437,600
Balance at Dec. 31, 2015	1,600	14,780,100	27,000,900	(504,100)	41,278,500
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	1,221,700	0	1,221,700
Balance at Dec. 31, 2016	$ 1,600	$ 14,780,100	$ 28,222,600	$ (504,100)	$ 42,500,200