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Note 9 - Fair Value - Fair Values for Investments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Marketable equity securities, cost	$ 49,941,567		$ 49,941,567
Marketable equity securities	52,866,683		52,866,683
Marketable equity securities, realized gain (loss)			415,572
Marketable equity securities			2,925,116
Securities available for sale, realized gain (loss)			14,902
Securities available for sale, gain (loss)			(61,056)
Realized gain (loss)			430,474
Gain (loss)	2,813,544	$ 13,419	2,864,060	$ 126,722
Reported Value Measurement [Member]
Marketable equity securities, cost	52,866,683		52,866,683
U.S. Treasury notes, Fair Value	75,095,227		75,095,227
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Marketable equity securities	52,866,683		52,866,683
U.S. Treasury notes, Fair Value	$ 75,095,227		$ 75,095,227