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Pension Plans and Other Postretirement Benefit Plans - Additional Information (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]      
Payment for pension benefits $ 42,000 $ 22,000 $ 22,000
Percentage of service related net periodic benefit costs capitalized to utility property 40.00%    
Percentage of service related net periodic benefit costs recorded to operating expenses 60.00%    
Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member] | Executive Officer [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Deferred compensation, earlier of retirement, termination, disability or death, percent 75.00%    
Deferred compensation incentive payments, percent 100.00%    
Equity Securities      
Defined Benefit Plan Disclosure [Line Items]      
Target investment allocation 55.00% 35.00%  
Debt Securities      
Defined Benefit Plan Disclosure [Line Items]      
Target investment allocation 40.00% 49.00%  
Real Estate [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target investment allocation 5.00% 7.00%  
Absolute Return [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Target investment allocation 0.00% 9.00%  
Pension Plans, Defined Benefit [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Expected contributions to pension plan $ 42,000    
Other Postretirement Benefits [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Expected contributions to pension plan $ 7,200    
Other Postretirement Benefits [Member] | Equity Securities      
Defined Benefit Plan Disclosure [Line Items]      
Target investment allocation 60.00% 60.00%  
Other Postretirement Benefits [Member] | Debt Securities      
Defined Benefit Plan Disclosure [Line Items]      
Target investment allocation 40.00% 40.00%