Retirement Plans (Components of Net Periodic Benefits Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,980	$ 2,800
Interest cost	5,788	3,417
Expected return on plan assets	(11,178)	(11,475)
Amortization of net (gain) or loss and prior service costs	1,770	1,348
Net periodic benefit cost	(1,640)	(3,910)
Other Post-Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	(31)	25
Interest cost	216	77
Amortization of net (gain) or loss and prior service costs	(251)	(139)
Net periodic benefit cost	$ (66)	$ (37)