Postretirement Benefit Plans (Amounts Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Postretirement Health And Life Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued benefit liability	$ 399	$ 342
Director's Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued benefit liability	1,195	1,142
Scottdale Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued pension benefit (asset) liability	(458)	$ 462
Riverview Defined Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued pension benefit (asset) liability	$ (819)