Benefit Plans - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension and Supplemental Executive Retirement Plans
Defined Benefit Plan Disclosure [Line Items]
Net Actuarial (Gain)/Loss	$ 84,045	$ 98,899
Net Prior Service Cost/(Credit)	(747)	(988)
Net Transition Obligation/(Asset)	0	0
Total at Year End	83,298	97,911	$ 98,589
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Net Actuarial (Gain)/Loss	(47,352)	(30,565)
Net Prior Service Cost/(Credit)	2,461	2,673
Net Transition Obligation/(Asset)	0	0
Total at Year End	$ (44,891)	$ (27,892)	$ (15,281)