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Retirement Plans - Additional Information (Details)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Defined Benefit Pension Plan    
Defined Benefit Plan Disclosure [Line Items]    
Contributions to pension plans $ 2.9 $ 4.4
Estimated employer contribution to pension plans during remainder of current fiscal year 13.0 13.0
Retiree Health Care Plan    
Defined Benefit Plan Disclosure [Line Items]    
Contributions to retiree health care plan $ 0.3 $ 0.6