Accumulated Other Comprehensive Loss (Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Balance	$ 130,556	$ 129,189	$ 131,047	$ 124,453	$ 131,047	$ 125,940	$ 125,940
Balance	133,787	130,556	129,189	130,237	133,787	130,237	131,047
Accumulated Other Comprehensive Loss [Member]
Balance	(28,468)	(33,198)	(28,863)	(27,483)	(28,863)	(25,971)	(25,971)
Other comprehensive income/(loss) before reclassifications	(586)	4,519	(4,670)				(4,052)
Amounts reclassified from accumulated other comprehensive loss	322	211	335				1,160
Balance	(28,732)	(28,468)	(33,198)	(25,851)	(28,732)	(25,851)	(28,863)
Investment securities- with OTTI [Member]
Balance	(1,504)	(3,048)	(3,277)		(3,277)	(2,542)	(2,542)
Other comprehensive income/(loss) before reclassifications	550	1,581	266	518	2,397	(914)	(587)
Amounts reclassified from accumulated other comprehensive loss	(37)	(37)	(37)				(148)
Balance	(991)	(1,504)	(3,048)		(991)		(3,277)
Investment securities- all other [Member]
Balance	(3,306)	(5,227)	(25)		(25)	(853)	(853)
Other comprehensive income/(loss) before reclassifications	(518)	2,034	(5,202)	(235)	(3,686)	1,791	1,291
Amounts reclassified from accumulated other comprehensive loss		(113)					(463)
Balance	(3,824)	(3,306)	(5,227)		(3,824)		(25)
Investment securities HTM [Member]
Balance	(236)	(270)	(315)		(315)	(899)	(899)
Amounts reclassified from accumulated other comprehensive loss	31	34	45				584
Balance	(205)	(236)	(270)		(205)		(315)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Balance	(583)	(549)	(954)		(954)	(85)	(85)
Other comprehensive income/(loss) before reclassifications	79	(34)	405				(869)
Balance	(504)	(583)	(549)		(504)		(954)
Defined Benefit Plans Adjustments [Member] | Pension [Member]
Balance	(21,287)	(22,497)	(22,630)		(22,630)	(20,417)	(20,417)
Other comprehensive income/(loss) before reclassifications	(697)	938	(139)	$ 1,385	102	(655)	(3,262)
Amounts reclassified from accumulated other comprehensive loss	273	272	272				1,049
Balance	(21,711)	(21,287)	(22,497)		(21,711)		(22,630)
Defined Benefit Plans Adjustments [Member] | SERP [Member]
Balance	(1,552)	(1,607)	(1,662)		(1,662)	$ (1,175)	(1,175)
Other comprehensive income/(loss) before reclassifications							(625)
Amounts reclassified from accumulated other comprehensive loss	55	55	55				138
Balance	$ (1,497)	$ (1,552)	$ (1,607)		$ (1,497)		$ (1,662)