Note 10 - Commitments and Contingencies (Details Textual)	12 Months Ended
	Dec. 31, 2022 USD ($) T bbl	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($) a
Oncor [Member]
Letters of Credit Outstanding, Amount				$ 1,900,000
TXU Energy Retail Company LLC [Member]
Letters of Credit Outstanding, Amount		$ 1,700,000
TEXAS
Area of Land (Acre) | a				80
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	22,800
Supply Commitment, Amount Committed	$ 18,300,000
Sand Commitments [Member]
Supply Commitment, Amount Committed	$ 4,600,000
Supply Commitment, Minimum Tons of Sand		600,000
Supply Commitment, Sand Purchased | T	279,000
Other Noncurrent Assets [Member]
Operating Lease, Right-of-Use Asset	$ 333,000		$ 852,000
Other Liabilities [Member]
Operating Lease, Liability, Total	$ 343,000		856,000
Other Current Liabilities [Member]
Operating Lease, Liability, Noncurrent			513,000
Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Noncurrent			$ 343,000