Note 10 - Commitments and Contingencies (Details Textual)	12 Months Ended
	Dec. 31, 2024 USD ($) T bbl	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2022 USD ($) T
Operating Lease, Right-of-Use Asset	$ 1,400,000		$ 510,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets		Other noncurrent assets
Operating Lease, Liability, Total	$ 1,389,000		$ 528,000
Operating Lease, Liability, Current	$ 719,000		$ 528,000
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	us-gaap_LiabilitiesCurrent		us-gaap_LiabilitiesCurrent
Operating Lease, Liability, Noncurrent	$ 670,000		$ 0
Contributions in Aid of Construction	27,200,000	$ 5,400,000
TXU Energy Retail Company LLC [Member]
Letters of Credit Outstanding, Amount				$ 4,600,000
Crude Oil Delivery Commitments [Member]
Supply Commitment, Minimum Volume Commitment	$ 138,700,000
Supply Commitment, Gross Barrels of Oil Delivered Per Day, Remaining Term of Contract (Barrel of Oil) | bbl	23,500
Supply Commitment, Remaining Term of Contract (Year)	8 years
Number of Barrels, Delivered (Barrel of Oil) | bbl	31,196
Supply Commitment, Amount Committed	$ 130,300,000
Sand Commitments [Member]
Supply Commitment, Amount Committed	$ 5,200,000
Supply Commitment, Minimum Tons of Sand (US Ton) | T				750,000
Supply Commitment, Tons of Sand Received | T	547,000
Supply Commitment, Tons of Sand Remaining | T	203,000