SUPPLEMENTARY OIL AND NATURAL GAS INFORMATION (UNAUDITED) - PROVED RESERVES (Details) bbl in Thousands, Mcf in Thousands, Boe in Thousands	12 Months Ended
	Sep. 30, 2025 Boe bbl Mcf	Sep. 30, 2024 Boe bbl Mcf
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period | Boe	2,423	2,343
Revisions of previous estimates | Boe	(102)	457
Extensions, discoveries and other additions | Boe		184
Acquisitions of reserves | Boe		9
Less sales of reserves | Boe	(527)	(79)
Less production | Boe	(414)	(491)
Balance at the end of the period | Boe	1,380	2,423
Canada
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period | Boe	1,915	1,772
Revisions of previous estimates | Boe	(65)	430
Extensions, discoveries and other additions | Boe		184
Acquisitions of reserves | Boe		9
Less sales of reserves | Boe	(102)	(79)
Less production | Boe	(368)	(401)
Balance at the end of the period | Boe	1,380	1,915
United States
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period | Boe	508	571
Revisions of previous estimates | Boe	(37)	27
Extensions, discoveries and other additions | Boe		0
Acquisitions of reserves | Boe		0
Less sales of reserves | Boe	(425)	0
Less production | Boe	(46)	(90)
Balance at the end of the period | Boe	0	508
Oil
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period	982	899
Revisions of previous estimates	(66)	219
Extensions, discoveries and other additions		117
Acquisitions of reserves		4
Less sales of reserves	(99)	(54)
Less production	(174)	(203)
Balance at the end of the period	643	982
Oil | Canada
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period	892	787
Revisions of previous estimates	(65)	222
Extensions, discoveries and other additions		117
Acquisitions of reserves		4
Less sales of reserves	(20)	(54)
Less production	(164)	(184)
Balance at the end of the period	643	892
Oil | United States
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period	90	112
Revisions of previous estimates	(1)	(3)
Extensions, discoveries and other additions		0
Acquisitions of reserves		0
Less sales of reserves	(79)	0
Less production	(10)	(19)
Balance at the end of the period	0	90
Natural gas liquids
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period	363	327
Revisions of previous estimates	22	85
Extensions, discoveries and other additions		15
Acquisitions of reserves		2
Less sales of reserves	(164)	(2)
Less production	(56)	(64)
Balance at the end of the period	165	363
Natural gas liquids | Canada
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period	199	150
Revisions of previous estimates	44	70
Extensions, discoveries and other additions		15
Acquisitions of reserves		2
Less sales of reserves	(35)	(2)
Less production	(43)	(36)
Balance at the end of the period	165	199
Natural gas liquids | United States
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period	164	177
Revisions of previous estimates	(22)	15
Extensions, discoveries and other additions		0
Acquisitions of reserves		0
Less sales of reserves	(129)	0
Less production	(13)	(28)
Balance at the end of the period	0	164
Natural gas
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period | Mcf	6,455	6,701
Revisions of previous estimates | Mcf	(329)	908
Extensions, discoveries and other additions | Mcf		313
Acquisitions of reserves | Mcf		16
Less sales of reserves | Mcf	(1,592)	(139)
Less production | Mcf	(1,105)	(1,344)
Balance at the end of the period | Mcf	3,429	6,455
Natural gas | Canada
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period | Mcf	4,941	5,010
Revisions of previous estimates | Mcf	(263)	826
Extensions, discoveries and other additions | Mcf		313
Acquisitions of reserves | Mcf		16
Less sales of reserves | Mcf	(283)	(139)
Less production | Mcf	(966)	(1,085)
Balance at the end of the period | Mcf	3,429	4,941
Natural gas | United States
Changes in the estimates of net interests in total proved reserves of oil, natural gas liquids and natural gas
Balance at the beginning of the period | Mcf	1,514	1,691
Revisions of previous estimates | Mcf	(66)	82
Extensions, discoveries and other additions | Mcf		0
Acquisitions of reserves | Mcf		0
Less sales of reserves | Mcf	(1,309)	0
Less production | Mcf	(139)	(259)
Balance at the end of the period | Mcf	0	1,514