Fair Value Measurements (Narrative) (Details) $ in Millions	3 Months Ended
Dec. 31, 2022 USD ($)
Fair Value Inputs Level3 [Member] \| Arkoma Basin [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held for sale working interest written down fair value less cost to sell	$ 5.1

Held for sale working interest written down fair value less cost to sell.

No definition available.

Name:	phx_HeldForSaleWorkingInterestWrittenDownFairValueLessCostToSell
Namespace Prefix:	phx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration