Note 4 - Fair Value Measurements - Assets and Liabilities Measured On Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Derivatives	$ 51,758	$ 13,591
Derivatives	5,342	4,075
Commodity Contract [Member]
Total liabilities	57,100
Commodity Contract [Member] | Fair Value, Recurring [Member]
Derivative assets	0	2,199
Derivatives	51,758	13,591
Derivatives	5,342	4,075
Total liabilities	57,100	17,666
Total recurring fair value measurements	(57,100)	(15,467)
Commodity Contract [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative assets	0	0
Derivatives	0	0
Derivatives	0	0
Total liabilities	0	0
Total recurring fair value measurements	0	0
Commodity Contract [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative assets	0	2,199
Derivatives	51,758	13,591
Derivatives	5,342	4,075
Total liabilities	57,100	17,666
Total recurring fair value measurements	(57,100)	(15,467)
Commodity Contract [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative assets	0	0
Derivatives	0	0
Derivatives	0	0
Total liabilities	0	0
Total recurring fair value measurements	$ 0	$ 0