Postretirement Benefit Plans - Amounts Recognized in Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Postretirement Health And Life Coverage
Defined Benefit Plan Disclosure [Line Items]
Accrued benefit liability	$ 271	$ 297
Director's Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Accrued benefit liability	1,306	1,299
Scottdale Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Accrued pension benefit asset	(809)	(917)
Riverview Defined Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Accrued pension benefit asset	$ (453)	$ (296)