Condensed Statements Of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Cash received from royalties and rents	$ 14,124,615	$ 22,559,309
Cash paid to suppliers and employees	(3,210,162)	(2,739,685)
Interest received	59,015	38,048
NET CASH PROVIDED BY OPERATING ACTIVITIES	10,973,468	19,857,672
Cash flows from investing activities:
U.S. Treasury securities purchased	(3,525,000)	(6,900,000)
U.S. Treasury securities matured	7,675,000	3,650,000
Expenditures for building and equipment	(23,206)
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	4,126,794	(3,250,000)
Cash flows from financing activities:
Distributions paid	(15,000,000)	(16,500,000)
NET CASH USED IN FINANCING ACTIVITIES	(15,000,000)	(16,500,000)
Net increase in cash and cash equivalents	100,262	107,672
Cash and cash equivalents at beginning of year	643,431	750,947
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 743,693	$ 858,619