Commitments and Contingencies - Narrative (Details) $ in Thousands, $ in Millions		3 Months Ended
	May 13, 2026 AUD ($)	Sep. 30, 2026 AUD ($)	Sep. 30, 2025 AUD ($)	Sep. 30, 2026 USD ($) well license	Sep. 30, 2026 AUD ($) well license	Jun. 30, 2026 USD ($)	May 12, 2026 AUD ($)	Sep. 29, 2025 AUD ($)	Dec. 19, 2024 AUD ($) bondFacility
Other Commitments [Line Items]
Number of wells | well				3	3
Number of potential additional performance bond facilities | bondFacility									2
Unamortized debt issuance expense					$ 0.4
Amortization of debt issuance costs		$ 0.1	$ 0.1
APA Group (APA) | Development Agreement ("DA")
Other Commitments [Line Items]
Guarantor obligation, construction costs covered by bank guarantees, percentage				67.00%	67.00%
APA Group (APA) | Financial Guarantee | Development Agreement ("DA")
Other Commitments [Line Items]
Guarantor obligations, current carrying value					$ 21.7
Bank guarantees released		6.4
Syndicated Facility Agreement
Other Commitments [Line Items]
Unamortized debt issuance expense				$ 1,500		$ 1,900
Letter of credit, facility A | Macquarie Bank Limited (“Macquarie”)
Other Commitments [Line Items]
Line of credit facility, maximum borrowing capacity									$ 25.0
Letters of credit outstanding, amount					28.1
Line of credit facility, remaining borrowing capacity					$ 7.7
Letter of credit, facility C | Macquarie Bank Limited (“Macquarie”)
Other Commitments [Line Items]
Line of credit facility, maximum borrowing capacity									5.0
Line of credit facility, conditions to issue stock, value, new issues									75.0
Letter of credit, facility B | Macquarie Bank Limited (“Macquarie”)
Other Commitments [Line Items]
Line of credit facility, maximum borrowing capacity									5.0
Line of credit facility, conditions to issue stock, value, new issues									62.5
Letter of credit facility A, B and C | Macquarie Bank Limited (“Macquarie”)
Other Commitments [Line Items]
Line of credit facility, current borrowing capacity									$ 35.0
Line of credit | Syndicated Facility Agreement
Other Commitments [Line Items]
Line of credit facility, maximum borrowing capacity	$ 40.0						$ 35.0	$ 179.8
Increase in maximum borrowing capacity	5.0
Minimum liquidity threshold	$ 10.0						$ 20.0
Letter of credit | Line of credit
Other Commitments [Line Items]
Interest rate, stated percentage				12.00%	12.00%
Letter of credit | Macquarie Bank Limited (“Macquarie”)
Other Commitments [Line Items]
Line of credit facility, covenants, minimum liquidity					$ 10.0
Line of credit facility, covenants, minimum current ratio				100.00%	100.00%
Line of credit facility, establishment fee		$ 0.5
Line of credit, drawdown fee percentage		10.00%
Line of credit facility, commitment fee percentage		4.00%
Letter of credit, facility B and C | Macquarie Bank Limited (“Macquarie”)
Other Commitments [Line Items]
Line of credit facility, remaining borrowing capacity					$ 0.1
Letter of credit, facility d | Macquarie Bank Limited (“Macquarie”)
Other Commitments [Line Items]
Line of credit facility, remaining borrowing capacity					$ 4.2
Sweetpea
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				$ 24,117		24,028
Number of licenses | license				2	2
Sweetpea | EP 136
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				$ 14,600
Extension of permit period		18 months
Sweetpea | EP 143
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				9,500
EP 161
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				$ 6,099		6,024
Number of wells | well				2	2
Beetaloo Joint Venture
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				$ 56,634		73,322
Number of wells | well				4	4
Beetaloo Joint Venture | EP 76
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				$ 14,300
Beetaloo Joint Venture | EP 98
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				28,100
Beetaloo Joint Venture | EP 117
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				14,300
Midstream
Other Commitments [Line Items]
Committed at the reporting date but not recognized as liabilities, payable:				$ 6,995		$ 22,957