Regulatory Matters - Schedule of Changes in The Deferred Fuel and Purchased Power Regulatory Asset (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Change in regulatory asset
Deferred fuel and purchased power costs	$ 26,521	$ 25,228
Amounts charged to customers	(120,157)	(84,789)
APS
Change in regulatory asset
Deferred fuel and purchased power costs	26,521	25,228
Amounts charged to customers	(120,157)	(84,789)
Power Supply Adjustor (PSA) | ACC | APS
Change in regulatory asset
Balance at beginning of period	149,068	287,597
Deferred fuel and purchased power costs	26,521	25,228
Amounts charged to customers	(120,157)	(84,789)
Balance at end of period	$ 55,432	$ 228,036