v3.26.3
Financial Instruments and Risk Management (Tables)
 9 Months Ended
Sep. 30, 2026
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Volumes Per Day Associated with Outstanding Natural Gas Derivative Contracts and the Weighted Average Prices for these Contracts
At September 30, 2025, volumes per day associated with outstanding natural gas derivative contracts and the weighted average prices for these contracts were as follows:
NYMEX Henry HubAreaCommodityVolumes MMCF/dPrice/MCFStart DateEnd Date
Fixed price derivative swapUnited StatesNatural Gas60$3.74 10/1/202512/31/2025
Schedule of Recognized Gains and Losses for Derivative Instruments Not Designated as Hedging Instruments
For the three and nine months ended September 30, 2026 and 2025, the gains and losses recognized in the Consolidated Statements of Operations for derivative instruments not designated as hedging instruments are presented in the following table:
(Thousands of dollars)Three Months Ended
September 30,		Nine Months Ended September 30,
Type of Derivative ContractStatement of Operations Location2026202520262025
Commodity swapsGain on derivative instruments$— $5,722 $— $7,071 
Schedule of Carrying Value of Assets and Liabilities Recorded at Fair Value on Recurring Basis
The fair value measurements for these assets and liabilities at September 30, 2026 and December 31, 2025, are shown in the following table.
September 30, 2026December 31, 2025
(Thousands of dollars)Level 1Level 2Level 3TotalLevel 1Level 2Level 3Total
Liabilities:
Nonqualified employee savings plan$21,905 $— $— $21,905 $22,205 $— $— $22,205 
$21,905 $— $— $21,905 $22,205 $— $— $22,205 
Schedule of Carrying Amounts and Estimated Fair Values of Financial Instruments
The following table presents the carrying amounts and estimated fair values of financial instruments held by the Company at September 30, 2026 and December 31, 2025. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties. The table excludes cash and cash equivalents, trade accounts receivable, trade accounts payable and accrued expenses, all of which had fair values approximating carrying amounts. The fair value of current and long-term debt was estimated based on rates offered to the Company at that time for debt of the same maturities. Substantially all of the Company’s long-term debt is actively traded in open markets, and accordingly, is classified as Level 1 in the
fair value hierarchy. The Company has off-balance sheet exposures relating to certain letters of credit. The fair value of these, which represents fees associated with obtaining the instruments, was minimal.
September 30, 2026December 31, 2025
(Thousands of dollars)Carrying
Amount		Fair
Value		Carrying
Amount		Fair
Value
Financial liabilities:
Current and long-term debt
$1,634,352 $1,480,834 $1,385,080 $1,326,101 
Schedule of Fair Value Information Associated with Impaired Properties
The fair value information associated with the impaired properties is presented in the following tables.
Nine Months Ended September 30, 2025
Net Book
Value
Prior to
Impairment		Total
Pretax
Impairment
Fair Value
(Thousands of dollars)Level 1Level 2Level 3
Property, plant and equipment:
Impaired proved properties
United States - Offshore$— $— $42,397 $157,399 $115,002