Note 8 - Commodity Derivative Activities - Outstanding Commodity (Details) - Not Designated as Hedging Instrument [Member]	3 Months Ended
	Mar. 31, 2019 USD ($) MMBTU bbl
Natural Gas Swap With SunTrust Bank [Member]
Fixed Price	2.951
Daily Volume, Natural Gas swaps (Millions of British Thermal Unit) | MMBTU	30,000
The 2019 Oil Swaps [Member]
Daily Volume, Oil Swaps (Barrel of Oil) | bbl	308
Total Volume, Oils swaps (Barrel of Oil) | bbl	84,775
Fixed Price	51.08
Fair Value at period end	$ (742)
Total Crude Oil [Member]
Fair Value at period end	(742)
The 2020 Natural Gas Swaps [Member]
Fair Value at period end	$ (787)
Daily Volume, Natural Gas swaps (Millions of British Thermal Unit) | MMBTU	70,000
Total Volume, Natural Gas swaps (Millions of British Thermal Unit) | MMBTU	6,370,000
The 2020 Natural Gas Swaps [Member] | Minimum [Member]
Fixed Price	2.873
The 2019 Natural Gas Swaps [Member]
Fixed Price	2.887
Fair Value at period end	$ 2,613
Daily Volume, Natural Gas swaps (Millions of British Thermal Unit) | MMBTU	100,000
Total Volume, Natural Gas swaps (Millions of British Thermal Unit) | MMBTU	27,500,000
Total Natural Gas [Member]
Fair Value at period end	$ 1,826
Crude Oil and Natural Gas Swaps [Member]
Fair Value at period end	$ 1,084