Derivatives (Effect of Cash Flow Hedge Accounting on Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives		$ (38)	$ (10)	$ (449)	$ 174
Amount reclassified from AOCI into income (expense)	[1],[2]	$ (17)	$ (1)	(43)	$ 21
Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives				449		$ (48)
Amount reclassified from AOCI into income (expense)				$ 43		$ (9)

[1] Amounts are included in interest expense on short-term borrowings and repurchase agreements on the Consolidated Statements of Income.

[2] Income tax amounts are included in the provision for income taxes on the Consolidated Statements of Income.