Note 3 - Derivative Financial Instruments - Derivative Financial Instruments - Schedule of Open Crude Oil and Natural Gas Derivative Contracts (Details)	3 Months Ended
	Sep. 30, 2020 Boe MMBTU
Crude Oil Derivative Swap Q4 2020 [Member]
Crude oil volume (Barrel of Oil Equivalent)	552,000
Weighted average price	60.65
Crude Oil Derivative Swap Q1 - Q4 2021 [Member]
Crude oil volume (Barrel of Oil Equivalent)	1,460,000
Weighted average price	55.16
Crude Oil Basis Swap 1 Q4 2020 [Member]
Crude oil volume (Barrel of Oil Equivalent)	598,000	[1]
Weighted average price	(1.50)	[1]
Crude Oil Basis Swap 2 Q4 2020 [Member]
Crude oil volume (Barrel of Oil Equivalent)	92,000	[2]
Weighted average price	2.55	[2]
Crude Oil Basis Swap 3 Q4 2020 [Member]
Crude oil volume (Barrel of Oil Equivalent)	552,000	[3]
Weighted average price	(1.79)	[3]
Crude Oil Basis Swap Q1 - Q4 2021 [Member]
Crude oil volume (Barrel of Oil Equivalent)	1,825,000	[1]
Weighted average price	1.05	[1]
Natural Gas Derivative Swap Q4 2021 [Member]
Crude oil volume (Barrel of Oil Equivalent) | MMBTU	644,000
Weighted average price	2.85
Natural Gas Derivative Swap Q1 - Q4 2021 [Member]
Crude oil volume (Barrel of Oil Equivalent) | MMBTU	4,380,000
Weighted average price	2.76
Natural Gas Basis Swap Q4 2021 [Member]
Crude oil volume (Barrel of Oil Equivalent) | MMBTU	644,000	[4]
Weighted average price	(1.07)	[4]
Natural Gas Basis Swap Q1 - Q4 2021 [Member]
Crude oil volume (Barrel of Oil Equivalent) | MMBTU	4,380,000	[4]
Weighted average price	(0.45)	[4]

[1] The basis differential price is between WTI Midland Crude and the WTI NYMEX.

[2] The basis differential price is between WTI Houston and the WTI NYMEX.

[3] The swap is between WTI Roll and the WTI NYMEX.

[4] The basis differential price is between W. Texas (WAHA) and the Henry Hub NYMEX.