Regulatory Assets And Liabilities - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 19, 2023	Dec. 31, 2022
Schedule Of Regulatory Assets And Liabilities [Line Items]
Regulatory assets	$ 94,274		$ 37,249
Winter Storm Elliott [Member]
Schedule Of Regulatory Assets And Liabilities [Line Items]
Non-performance charges		$ 13,600
Capacity performance bonus payments		18,300
Net regulatory liability		$ 4,700
Amortization of net regulatory asset	$ 4,700
PJM Capacity Performance Event [Member]
Schedule Of Regulatory Assets And Liabilities [Line Items]
Regulatory assets			$ 20,106