Statement of Stockholders' Equity - USD ($)	Dividend Declared [Member] Retained Earnings [Member]	Dividend Declared [Member]	Dividend Paid [Member] Retained Earnings [Member]	Dividend Paid [Member]	Common Stock [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2015					4,594,319
Balance at Dec. 31, 2015					$ 459,432	$ 72,361	$ 14,050,021	$ 14,581,814
Change in unrealized gains on marketable securities, net						103,273		103,273
Net income							2,581,142	2,581,142
Dividends	$ (8,873)	$ (8,873)	$ (3,436,867)	$ (3,436,867)				(3,445,740)
Balance (in shares) at Dec. 31, 2016					4,594,319
Balance at Dec. 31, 2016					$ 459,432	175,634	13,185,423	13,820,489
Change in unrealized gains on marketable securities, net						255,796		255,796
Net income							3,844,290	3,844,290
Dividends	$ (16,684)	$ (16,684)	$ (6,507,249)	$ (6,507,249)				(6,523,933)
Reclassification of tax effect from accumulated other comprehensive income due to federal tax rate change						34,595	(34,595)
Balance (in shares) at Dec. 31, 2017					4,594,319
Balance at Dec. 31, 2017					$ 459,432	$ 466,025	$ 10,471,185	$ 11,396,642