Note 10 - Commitments and Contingencies (Details Textual) MMBbls in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) T bbl MMBbls	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)
TXU Energy Retail Company LLC [Member]
Letters of Credit Outstanding, Amount			$ 3,900,000
Crude Oil Delivery Commitments [Member]
Supply Commitment, Gross Barrels of Oil Delivered Per Day, Year One (Barrel of Oil) | bbl	5,000
Supply Commitment, Gross Barrels of Oil Delivered Per Day, Year Two (Barrel of Oil) | bbl	7,500
Supply Commitment, Gross Barrels of Oil Delivered Per Day, Remaining Term of Contract (Barrel of Oil) | bbl	10,000
Supply Commitment, Remaining Term of Contract (Year)	8 years
Number of Barrels, Delivered (Barrel of Oil) | bbl	29,600
Supply Commitment, Percent of Contracted Volume Delivered	72.00%
Supply Commitment, Remaining Minimum Amount Committed, Volume | MMBbls	9.5
Supply Commitment, Amount Committed	$ 7,800,000
Sand Commitments [Member]
Supply Commitment, Amount Committed	$ 9,500,000
Supply Commitment, Minimum Tons of Sand			1.6
Supply Commitment, Sand Purchased | T	1.2
Other Noncurrent Assets [Member]
Operating Lease, Right-of-Use Asset	$ 510,000	$ 333,000
Other Liabilities [Member]
Operating Lease, Liability, Total	$ 528,000	$ 343,000