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Pension Benefits - Additional Information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]    
Period of service to become eligible 6 months  
Quantifying Misstatement in Current Year Financial Statements, Amount   $ 269,000,000
Defined Benefit Plan, Accumulated Benefit Obligation $ 2,900,000 1,700,000
Unrecorded Pension Expense [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Quantifying Misstatement in Current Year Financial Statements, Amount   269,000
Subsidiaries [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Pension expense $ 300,000 $ 700,000