Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 8,778,105	$ 8,299,873
Less accumulated depreciation	2,019,142	1,930,688
Net property, plant and equipment	$ 6,398,275	$ 6,039,801
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant, and equipment, net	Property, plant, and equipment, net
Electric Plant
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Equipment	$ 6,034,159	$ 5,462,229
Natural Gas Plant
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Equipment	1,615,228	1,506,943
Plant Acquisition adjustment [Member]
Property, Plant and Equipment [Line Items]
Plant acquisition adjustment(1)	686,328	686,328
Common Plant
Property, Plant and Equipment [Line Items]
Common and Other Plant	277,623	267,132
Construction work in progress
Property, Plant and Equipment [Line Items]
Construction work in process	164,767	377,241
Computer Software, Intangible Asset
Property, Plant and Equipment [Line Items]
Less accumulated amortization	$ (360,688)	$ (329,384)