Postretirement Benefits - Schedule of Pension Liability (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Pension benefit obligation	$ 605,504	$ 562,567
Qualified Plan | Pension Plans | Defined Benefit Plan, Funded Plan
Defined Benefit Plan Disclosure [Line Items]
Pension benefit obligation	534,621	492,103
Nonqualified Plan | SERP
Defined Benefit Plan Disclosure [Line Items]
Pension benefit obligation	$ 70,883	$ 70,464