Accumulated Other Comprehensive Income (Schedule of Changes In Each Component of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 632,430	$ 691,685	$ 681,105	$ 701,106
Other comprehensive (loss) income, net of tax	(39,269)	6,938	(98,243)	(8,667)
Ending balance	591,993	695,476	591,993	695,476
Defined Benefit Pension Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,485)	(5,661)	(3,485)	(5,661)
Ending balance	(3,485)	(5,661)	(3,485)	(5,661)
Securities available-for-sale:
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(41,229)	21,289	17,745	36,894
Other comprehensive income (loss) before reclassifications	(39,269)	6,960	(98,243)	(8,430)
Amounts reclassified from other comprehensive income		(22)		(237)
Other comprehensive (loss) income, net of tax	(39,269)	6,938	(98,243)	(8,667)
Ending balance	(80,498)	28,227	(80,498)	28,227
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(44,714)	15,628	14,260	31,233
Other comprehensive income (loss) before reclassifications	(39,269)	6,960	(98,243)	(8,430)
Amounts reclassified from other comprehensive income		(22)		(237)
Other comprehensive (loss) income, net of tax	(39,269)	6,938	(98,243)	(8,667)
Ending balance	$ (83,983)	$ 22,566	$ (83,983)	$ 22,566