Securities (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) security	Mar. 31, 2019 USD ($)	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2019 USD ($)
Schedule Of Marketable Securities [Line Items]
Proceeds from sales of securities available for sale	$ 6,200	$ 16,800
Investments held having OTTI losses	$ 0	$ 0
Number of securities with unrealized losses | security	65
Securities with amortized costs	$ 46,100				$ 47,300
Securities purchased from single issuer other than U.S. Treasury issue and other U.S. Government agencies	$ 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	43
Asset-backed Securities, Securitized Loans and Receivables [Member]
Schedule Of Marketable Securities [Line Items]
Investment grade corporate obligations comprise securities with unrealized losses | security	10
Corporate Debt Securities [Member]
Schedule Of Marketable Securities [Line Items]
Investment grade corporate obligations comprise securities with unrealized losses | security	12
Federal Reserve Bank Advances [Member]
Schedule Of Marketable Securities [Line Items]
Debt Instrument, Collateral Amount	$ 5,500				$ 5,800