Statements of Stockholders' Equity - USD ($)	Dividend Declared [Member] Common Stock [Member]	Dividend Declared [Member] AOCI Attributable to Parent [Member]	Dividend Declared [Member] Retained Earnings [Member]	Dividend Declared [Member]	Dividend Paid [Member] Common Stock [Member]	Dividend Paid [Member] AOCI Attributable to Parent [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, 2017									4,594,319
Balance at Dec. 31, 2017									$ 459,432	$ 466,025	$ 10,471,185	$ 11,396,642
Reclassification of accumulated unrealized gains on marketable securities in accordance with ASU 2016-01(See Note B)										(466,025)	466,025
Net income											4,352,331	4,352,331
Dividends declared			$ (7,796)	$ (7,796)			$ (4,816,239)	$ (4,816,239)				(4,824,035)
Balance (in shares) at Dec. 31, 2018									4,594,319
Balance at Dec. 31, 2018									$ 459,432		10,465,506	10,924,938
Net income											4,761,711	4,761,711
Dividends declared			$ (3,829)	$ (3,829)			$ (5,049,922)	$ (5,049,922)				(5,053,751)
Balance (in shares) at Dec. 31, 2019									4,594,319
Balance at Dec. 31, 2019									$ 459,432		$ 10,173,466	$ 10,632,898