Employee Benefit Plans and Other Postretirement Benefits - Schedule Of Net Periodic Benefit Cost Recognized In Accumulated And Other Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Pension and SERPA Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service credits	$ (6,489)	$ (14,371)
Net actuarial loss	496,919	593,608
Amounts included in other comprehensive income, net of tax	490,430	579,237
Postretirement Health Coverage
Defined Benefit Plan Disclosure [Line Items]
Prior service credits	(7,559)	(9,381)
Net actuarial loss	(1,321)	12,005
Amounts included in other comprehensive income, net of tax	$ (8,880)	$ 2,624