Note 2 - Basis of Presentation and Summary of Significant Accounting Policies (Details Textual) - USD ($)		1 Months Ended	3 Months Ended		9 Months Ended
		Feb. 28, 2022	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Dec. 31, 2021
Accounts Receivable, after Allowance for Credit Loss, Current, Total			$ 46,167,000		$ 46,167,000	$ 39,378,000
Income Taxes Receivable			3,200,000		3,200,000	3,200,000
Oil and Gas Joint Interest Billing Receivables			1,900,000		1,900,000	3,100,000
Accounts Receivable, Allowance for Credit Loss, Current			0		0	771,000
Prepaid Expense			15,100,000		15,100,000	7,200,000
Inventory, Raw Materials and Supplies, Gross, Total			4,000,000.0		4,000,000.0	3,300,000
Inventory, LIFO Reserve			0		0	0
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance			497,000		497,000	438,000
Payments of Debt Issuance Costs			6,449,000	$ 2,000
Amortization of Debt Issuance Costs			645,000	29,000
Debt Instrument, Unamortized Discount, Total	[1]		13,927,000		13,927,000	(0)
Amortization of Debt Discount (Premium)			893,000	0
Accounts Payable and Accrued Liabilities, Current, Total			179,600,000		179,600,000	103,000,000.0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total			$ 0		0
Number of Operating Segments			1
Minimum [Member]
Oil and Natural Gas Marketing Contracts, Term Over Which Consideration is Received from Purchaser (Month)			1 month
Maximum [Member]
Oil and Natural Gas Marketing Contracts, Term Over Which Consideration is Received from Purchaser (Month)			2 months
Senior Unsecured Notes and Revolving Credit Facility [Member]
Payments of Debt Issuance Costs			$ 6,400,000		9,000,000.0
Amortization of Debt Issuance Costs			644,000	29,000
Senior Unsecured Notes Due 2024 [Member]
Payments of Debt Issuance Costs		$ 21,200,000
Debt Instrument, Unamortized Discount, Total		$ 14,800,000
Amortization of Debt Discount (Premium)			$ 893,000	$ 0
Transportation Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)			5 years
Field Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)			7 years
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Largest Purchaser [Member]
Concentration Risk, Percentage			93.00%	96.00%
Refunds From Pipe Suppliers [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total			$ 0		0	3,200,000
Aid-in-construction Receivables [Member] | WTG Gas Processing, L.P. [Member]
Accounts Receivable, after Allowance for Credit Loss, Total			3,800,000		3,800,000	3,900,000
Crude Oil, Natural Gas and Natural Gas Liquids [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total			$ 41,100,000		$ 41,100,000	$ 29,000,000.0

[1] Discounts as of March 31, 2022 and December 31, 2021 consisted of $14.8 million and zero, respectively, in discounts less accumulated amortization of $893,000 and zero, respectively.