Condensed Statements Of Cash Flows (USD $)	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Cash flows from operating activities:
Cash received from royalties and rents	$ 15,217,173		$ 11,575,918
Cash paid to suppliers and employees	(1,401,235)		(1,336,202)
Interest and related premium/discount received (paid)	11,285		(2,987)
NET CASH PROVIDED BY OPERATING ACTIVITIES	13,827,223		10,236,729
Cash flows from investing activities:
U.S. Treasury securities purchased	(5,000,000)		(4,425,000)
U.S. Treasury securities matured	3,050,000		3,325,000
NET CASH USED IN INVESTING ACTIVITIES	(1,950,000)		(1,100,000)
Cash flows from financing activities:
Distributions paid	(12,000,000)		(9,000,000)
NET CASH USED IN FINANCING ACTIVITIES	(12,000,000)		(9,000,000)
Net (decrease) increase in cash and cash equivalents	(122,777)		136,729
Cash and cash equivalents at beginning of year	750,947	[1]	668,310
CASH AND CASH EQUIVALENTS AT JUNE 30	$ 628,170		$ 805,039

[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.