Accumulated Other Comprehensive Income (Schedule of Changes In Each Component of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 681,105	$ 701,106
Other comprehensive loss, net of tax	(58,974)	(15,605)
Ending balance	632,430	691,685
Defined Benefit Pension Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,485)	(5,661)
Ending balance	(3,485)	(5,661)
Securities available-for-sale:
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	17,745	36,894
Other comprehensive loss before reclassifications	(58,974)	(15,390)
Amounts reclassified from other comprehensive income		(215)
Other comprehensive loss, net of tax	(58,974)	(15,605)
Ending balance	(41,229)	21,289
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	14,260	31,233
Other comprehensive loss before reclassifications	(58,974)	(15,390)
Amounts reclassified from other comprehensive income		(215)
Other comprehensive loss, net of tax	(58,974)	(15,605)
Ending balance	$ (44,714)	$ 15,628