Securities (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020 USD ($) security	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) security	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Schedule Of Marketable Securities [Line Items]
Proceeds from sales of securities available for sale	$ 4,600	$ 16,400	$ 25,200	$ 57,500
Investments held having OTTI losses	$ 0	$ 0	$ 0	$ 0
Number of securities with unrealized losses | security	53		53
Securities with amortized costs	$ 49,800		$ 49,800		$ 47,300
Securities purchased from single issuer other than U.S. Treasury issue and other U.S. Government agencies	0		$ 0		$ 0
Minimum percentage of securities purchased from U.S. Treasury issue and other U.S. Government agencies			10.00%		10.00%
U.S. Treasury Issue and Other U.S. Gov't Agencies [Member]
Schedule Of Marketable Securities [Line Items]
Securities with investment grade | security			32
Asset-backed Securities, Securitized Loans and Receivables [Member]
Schedule Of Marketable Securities [Line Items]
Investment grade corporate obligations comprise securities with unrealized losses | security			16
Corporate Debt Securities [Member]
Schedule Of Marketable Securities [Line Items]
Investment grade corporate obligations comprise securities with unrealized losses | security			5
Federal Reserve Bank Advances [Member]
Schedule Of Marketable Securities [Line Items]
Debt Instrument, Collateral Amount	$ 5,300		$ 5,300		$ 5,800