Condensed Statements Of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011
Cash flows from operating activities:
Cash received from royalties and rents	$ 22,559,309		$ 17,964,950
Cash paid to suppliers and employees	(2,739,685)		(2,386,888)
Interest received	38,048		13,749
NET CASH PROVIDED BY OPERATING ACTIVITIES	19,857,672		15,591,811
Cash flows from investing activities:
U.S. Treasury securities purchased	(6,900,000)		(6,075,000)
U.S. Treasury securities matured	3,650,000		4,275,000
Expenditures for building and equipment	0		(18,685)
NET CASH USED IN INVESTING ACTIVITIES	(3,250,000)		(1,818,685)
Cash flows from financing activities:
Distributions paid	(16,500,000)		(13,500,000)
NET CASH USED IN FINANCING ACTIVITIES	(16,500,000)		(13,500,000)
Net increase in cash and cash equivalents	107,672		273,126
Cash and cash equivalents at beginning of year	750,947	[1]	668,310
CASH AND CASH EQUIVALENTS AT SEPTEMBER 30	$ 858,619		$ 941,436

[1] The balance sheet at December 31, 2011, has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.