Derivatives, Hedges and Financial Instruments - Additional Information (Detail) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023 USD ($) MMBTU	Dec. 31, 2022 USD ($) MMBTU
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Financial instruments with fair values | $	$ 0	$ 0
Natural Gas Purchase Commitments [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Natural gas purchase commitments volume	7,200,000
Natural Gas Purchase Commitments [Member] | Level 2 [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Natural gas purchase commitments volume	0	0