Note 4 - Fair Value Measurements - Assets and Liabilities Measured On Recurring Basis (Details) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Derivatives	$ 39,911,000	$ 13,591,000
Derivatives	0	4,075,000
Commodity Contract [Member]
Commodity price derivatives	31,909,000
Total liabilities	31,909,000
Fair Value, Recurring [Member] | Commodity Contract [Member]
Commodity price derivatives	8,002,000	2,199,000
Commodity price derivatives	39,911,000	17,666,000
Total recurring fair value measurements	(31,909,000)	(15,467,000)
Derivatives		13,591,000
Derivatives		4,075,000
Total liabilities	39,911,000	17,666,000
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Commodity Contract [Member]
Commodity price derivatives	0	0
Commodity price derivatives	0	0
Total recurring fair value measurements	0	0
Derivatives		0
Derivatives		0
Total liabilities	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Commodity Contract [Member]
Commodity price derivatives	8,002,000	2,199,000
Commodity price derivatives	39,911,000	17,666,000
Total recurring fair value measurements	(31,909,000)	(15,467,000)
Derivatives		13,591,000
Derivatives		4,075,000
Total liabilities	39,911,000	17,666,000
Fair Value, Inputs, Level 3 [Member] | Commodity Contract [Member]
Commodity price derivatives		0
Commodity price derivatives		0
Total recurring fair value measurements		0
Derivatives		0
Derivatives		0
Total liabilities		$ 0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Commodity Contract [Member]
Commodity price derivatives	0
Commodity price derivatives	0
Total recurring fair value measurements	0
Total liabilities	$ 0