XML 117 R101.htm IDEA: XBRL DOCUMENT v3.22.0.1
Employee Benefit Plans: Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($)
$ in Thousands
Dec. 31, 2021
Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]    
Regulatory assets $ 796,599 $ 278,258
Benefit plan liabilities 123,925 150,556
Regulatory liabilities 502,951 532,720
Pension Plan    
Defined Benefit Plan Disclosure [Line Items]    
Regulatory assets 67,403 86,677
Current liabilities 0 0
Benefit plan liabilities 19,872 40,287
Regulatory liabilities 3,830 3,607
Supplemental Employee Retirement Plan    
Defined Benefit Plan Disclosure [Line Items]    
Regulatory assets 0 0
Current liabilities 2,156 1,927
Benefit plan liabilities 53,104 53,127
Regulatory liabilities 0 0
Other Postretirement Benefits Plan    
Defined Benefit Plan Disclosure [Line Items]    
Regulatory assets 11,660 16,102
Current liabilities 4,584 4,931
Benefit plan liabilities 50,949 57,142
Regulatory liabilities $ 2,447 $ 2,140