Regulatory Matters - Schedule of Changes in The Deferred Fuel and Purchased Power Regulatory Asset (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Change in regulatory asset
Deferred fuel and purchased power costs	$ 276,327	$ 244,109
Amounts charged to customers	(358,871)	(340,030)
APS
Change in regulatory asset
Deferred fuel and purchased power costs	276,327	244,109
Amounts charged to customers	(358,871)	(340,030)
Power Supply Adjustor (PSA) | ACC | APS
Change in regulatory asset
Balance at beginning of period	287,597	463,195
Deferred fuel and purchased power costs	276,327	244,109
Amounts charged to customers	(358,871)	(340,030)
Balance at end of period	$ 205,053	$ 367,274