Asset Acquisitions and Divestitures (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2020
Asset Acquisitions and Divestitures [Line Items]
Net Proceeds from Sale of Oil and Gas Producing Properties			$ 254,439,000	$ 0
Gain on Sale of California Assets	$ 12,736,000	$ 0	12,736,000	51,066,000
Net Proceeds from Sale of Timber Properties			0	104,582,000
Assets Held for Sale, Net					$ 53,400,000
Gain on Sale of Timber Properties				$ 51,100,000
Total Consideration for Asset Acquisition					$ 506,300,000
California Asset Sale [Member]
Asset Acquisitions and Divestitures [Line Items]
Consideration for Asset Sale	253,500,000		253,500,000
Net Proceeds from Sale of Oil and Gas Producing Properties	240,900,000
Maximum Annual Contingent Payments	10,000,000		10,000,000
Amount of Each Incremental Contingent Payment	1,000,000		1,000,000
Incremental Dollar Per Barrel That ICE Brent Average Exceeds Price	1		1
Gain on Sale of California Assets	12,700,000
Asset Retirement Obligation Reduction	50,100,000
California Asset Sale [Member] | Minimum [Member]
Asset Acquisitions and Divestitures [Line Items]
ICE Brent Average per Barrel	95		95
California Asset Sale [Member] | Maximum [Member]
Asset Acquisitions and Divestitures [Line Items]
ICE Brent Average per Barrel	105		105
California Asset Sale [Member] | Present Value of Contingent Consideration [Member]
Asset Acquisitions and Divestitures [Line Items]
Value of Contingent Consideration from Asset Sale	12,600,000		12,600,000
Full Cost Method of Accounting Assets [Member] | California Asset Sale [Member]
Asset Acquisitions and Divestitures [Line Items]
Property, Plant and Equipment Disposal	220,700,000		220,700,000
Assets Not Subject to Full Cost Method of Accounting [Member] | California Asset Sale [Member]
Asset Acquisitions and Divestitures [Line Items]
Property, Plant and Equipment Disposal	$ 32,800,000		$ 32,800,000