v3.26.1
Leases - Schedule of Lease and Non-lease Components for all Lease Agreements (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Right-of-use assets—Finance leases    
Right-of-use assets $ 302,732 $ 302,732
Less: Accumulated provision for depreciation (291,323) (288,688)
Total finance lease assets 11,409 14,044
Lease liabilities—Finance leases    
Obligations under finance leases 15,295 21,578
Long-term debt and finance leases due within one year 12,236 11,595
Total finance lease liabilities $ 27,531 $ 33,173
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Long-term debt and finance leases due within one year Long-term debt and finance leases due within one year
Right-of-use assets—Operating leases    
Electric plant in service, net $ 6,293 $ 7,357
Total operating lease assets $ 6,293 $ 7,357
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Public Utilities, Property Plant and Equipment, Plant in Service, Net Public Utilities, Property Plant and Equipment, Plant in Service, Net
Lease liabilities—Operating leases    
Capitalization—Other $ 4,323 $ 5,284
Other current liabilities 1,970 2,073
Total operating lease liabilities $ 6,293 $ 7,357
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Other Other
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Other current liabilities Other current liabilities
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]   Public Utilities, Property Plant and Equipment, Plant in Service, Net