Benefit Plans - Development of Funded Status (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension and Supplemental Executive Retirement Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	$ 261,330	$ 274,975
Projected Benefit Obligation	(261,330)	(274,975)	$ (391,698)
Plan Assets at Fair Value	235,612	250,674	391,555
Funded Status - Overfunded/(Underfunded)	(25,718)	(24,301)
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	30,238	29,580
Projected Benefit Obligation	(30,238)	(29,580)	(25,635)
Plan Assets at Fair Value	134,371	111,154	$ 140,839
Funded Status - Overfunded/(Underfunded)	$ 104,133	$ 81,574