v3.26.1
Fair Value Measurements
 6 Months Ended
Mar. 31, 2026
Fair Value Disclosures [Abstract]  
Fair Value Measurements Fair Value Measurements
 
    The FASB authoritative guidance regarding fair value measurements establishes a fair-value hierarchy and prioritizes the inputs used in valuation techniques that measure fair value. Those inputs are prioritized into three levels. Level 1 inputs are unadjusted quoted prices in active markets for assets or liabilities that the Company can access at the measurement date. Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly at the measurement date. Level 3 inputs are unobservable inputs for the asset or liability at the measurement date. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels.
 
    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.
    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 

    In exploring the potential sale of certain water disposal assets during the quarter ended December 31, 2024, the Company determined that the fair market value of such assets was less than the recorded net book value resulting in an impairment charge that reduced the net book value to fair market value. These assets are used to dispose of water from operations in the Integrated Upstream and Gathering segment.
 
Derivative Financial Instruments
 
    The derivative financial instruments reported in Level 2 at March 31, 2026 and September 30, 2025 include natural gas price swap agreements, natural gas no cost collars, and foreign currency contracts, all of which are used in the Company’s Integrated Upstream and Gathering segment. The fair value of the Level 2 price swap agreements and no cost collars is based on an internal cash flow model that uses observable inputs (i.e. SOFR based discount rates for the price swap agreements and basis differential information, if applicable, at active natural gas trading markets). The fair value of the Level 2 foreign currency contracts is determined using the market approach based on observable market transactions of forward Canadian currency rates. 

    The authoritative guidance for fair value measurements and disclosures require consideration of the impact of nonperformance risk (including credit risk) from a market participant perspective in the measurement of the fair value of assets and liabilities. At March 31, 2026, the Company determined that nonperformance risk associated with the price swap agreements, no cost collars and foreign currency contracts would have no material impact on its financial position or results of operation. To assess nonperformance risk, the Company considered information such as any applicable collateral posted, master netting arrangements, and applied a market-based method by using the counterparty's (assuming the derivative is in a gain position) or the Company’s (assuming the derivative is in a loss position) credit default swaps rates.