Note 7 - Business Segments, Risks and Major Customers - Table of Natural Gas Sales to Significant Purchasers as a Percentage of Consolidated Crude Oil and Natural Gas Sale (Details) - Customer Concentration Risk [Member] - Natural Gas Sales [Member]	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Concentration Risk, Percentage	38.00%	41.00%
Dominion Field Services, Inc. [Member]
Concentration Risk, Percentage	25.00%	27.00%
Interstate Gas Supply, Inc. [Member]
Concentration Risk, Percentage	13.00%	14.00%