Stanwell Liabilities (Narrative) (Details) T in Thousands, $ in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026 AUD ($)	Jun. 30, 2026 USD ($)	Jun. 30, 2026 AUD ($) T	Jun. 30, 2026 USD ($) T	Jun. 30, 2026 USD ($)	Dec. 31, 2025 USD ($)	Aug. 14, 2018 AUD ($)	Aug. 14, 2018 USD ($)
Contract Obligations [Line Items]
Deferred consideration liability					$ 362,318	$ 346,768
Contract obligations					0	21,173
Stanwell Reserve Area Deferred Consideration [Member]
Contract Obligations [Line Items]
Deferred consideration liability							$ 210.0	$ 155,200
Contractual pre-tax discount rate			13.00%	13.00%
Stanwell Prepaid Coal Supply Liability [Member]
Contract Obligations [Line Items]
Non-market portion of coal leases \| T			800	800
Prepayment, discount period			5 years	5 years
Prepaid coal supply liability interest rate			13.00%	13.00%
Contract obligations	$ 250.7		$ 250.7		178,000
Interest expense	$ 8.4	$ 5,900	$ 15.8	$ 11,100
Second Amendment Deed [Member]
Contract Obligations [Line Items]
Liquidity benchmark for prepayment settlement				$ 300,000
Prepayment and deferred payment balance interest rate			7.50%	7.50%
Accrued interest amount capped percent			120.00%	120.00%
Cash liquidity benchmark for distributions					300,000
Second Amendment Deed [Member] \| Minimum [Member]
Contract Obligations [Line Items]
Liquidity benchmark for prepayments				$ 200,000
Range of broader annual nominations \| T			1,200	1,200
Second Amendment Deed [Member] \| Maximum [Member]
Contract Obligations [Line Items]
Liquidity benchmark for prepayments				$ 250,000
Range of broader annual nominations \| T			2,240	2,240
Stanwell Prepayment And Deferred Payment [Member]
Contract Obligations [Line Items]
Contract obligations					65,270	$ 0
Cumulative rebate amount					$ 48,800
Change of control provision			2 years	2 years
Control of interest percent disposed to trigger payout in agreement			20.00%	20.00%