v3.26.1
Fair Value Measurements (Tables)
 6 Months Ended
Mar. 31, 2026
Fair Value Disclosures [Abstract]  
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis The following table sets forth, by level within the fair value hierarchy, the Company's financial assets and liabilities (as applicable) that were accounted for at fair value on a recurring basis as of March 31, 2026 and September 30, 2025. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement.  
Recurring Fair Value MeasuresAt fair value as of March 31, 2026
(Thousands of Dollars)   Level 1Level 2Level 3
Netting
Adjustments(1)
Total(1)
Assets:
 
    
Cash Equivalents – Money Market Mutual Funds$20,340 $— $— $— $20,340 
Derivative Financial Instruments:     
Over the Counter Swaps – Gas— 123,697 — (33,832)89,865 
Over the Counter No Cost Collars – Gas— 29,257 — (2,548)26,709 
Foreign Currency Contracts— 93 — (653)(560)
Other Investments:     
Balanced Equity Mutual Fund13,872 — — — 13,872 
Fixed Income Mutual Fund10,226 — — — 10,226 
Total$44,438 $153,047 $— $(37,033)$160,452 
Liabilities:     
Derivative Financial Instruments:     
Over the Counter Swaps – Gas$— $33,832 $— $(33,832)$— 
Over the Counter No Cost Collars – Gas— 2,548 — (2,548)— 
Foreign Currency Contracts— 889 — (653)236 
Total$— $37,269 $— $(37,033)$236 
Total Net Assets/(Liabilities)$44,438 $115,778 $— $— $160,216 

Recurring Fair Value MeasuresAt fair value as of September 30, 2025
(Thousands of Dollars)   Level 1Level 2Level 3
Netting
Adjustments(1)
Total(1)
Assets:
Cash Equivalents – Money Market Mutual Funds$30,551 $— $— $— $30,551 
Derivative Financial Instruments:
Over the Counter Swaps – Gas— 62,190 — (33,615)28,575 
Over the Counter No Cost Collars – Gas — 24,149 — (12,805)11,344 
Foreign Currency Contracts— 144 — (675)(531)
Other Investments:
Balanced Equity Mutual Fund13,786 — — — 13,786 
Fixed Income Mutual Fund10,082 — — — 10,082 
Total$54,419 $86,483 $— $(47,095)$93,807 
Liabilities:
Derivative Financial Instruments:
Over the Counter Swaps – Gas$— $34,169 $— $(33,615)$554 
Over the Counter No Cost Collars – Gas— 18,036 — (12,805)5,231 
Foreign Currency Contracts— 893 — (675)218 
Total$— $53,098 $— $(47,095)$6,003 
Total Net Assets/(Liabilities)$54,419 $33,385 $— $— $87,804 

(1)Netting Adjustments represent the impact of legally-enforceable master netting arrangements that allow the Company to net gain and loss positions held with the same counterparties. The net asset or net liability for each counterparty is recorded as an asset or liability on the Company’s balance sheet.
Schedule of Fair Value Measurements, Nonrecurring The following table presents impairments of assets associated with certain nonrecurring fair value measurements within Level 3 of the fair value hierarchy as of March 31, 2026 and 2025 (in thousands):
Impairments
Nonrecurring Fair Value MeasuresSix Months Ended March 31,
SegmentDate of MeasurementFair Value20262025
Impairment of Assets:
Water Disposal AssetsIntegrated Upstream and GatheringDecember 31, 2024$12,880 $— $33,453