Defined Pension Plans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension period	30 years
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension costs	$ 273	$ 1,029
Unfunded Supplemental Executive Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension costs	$ 160	$ 145