Pension, Savings, and Other Employee Benefits - Schedule Of Components Of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 30	$ 41	$ 37
Interest cost	30,207	27,877	29,380
Expected return on plan assets	(36,908)	(32,897)	(36,015)
Prior service cost/(credit)	0	0	52
Actuarial (gain)/loss	9,888	12,102	9,521
Net periodic benefit cost	3,217	7,123	2,975
ASC 715 settlement expense	0	0	43
Total periodic benefit costs	3,217	7,123	3,018
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	94	133	107
Interest cost	1,413	1,309	1,305
Expected return on plan assets	(1,136)	(1,074)	(947)
Prior service cost/(credit)	32	0	95
Actuarial (gain)/loss	(493)	(387)	(567)
Net periodic benefit cost	(90)	(19)	(7)
ASC 715 settlement expense	194	99	0
Total periodic benefit costs	$ 104	$ 80	$ (7)