Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Financial guarantees in connection with standby letters of credit	$ 0	$ 0	$ 0	$ 0
Standby letters of credit expiring within one year	91,500		91,500
Standby letters of credit expiring thereafter	10,500		10,500
Residential mortgage loan repurchase reserve liability	1,600		$ 1,600
Right to repurchase loans, period past due			90 days
GNMA Loans past due by 90 days, but not yet repurchased	$ 20,000		$ 20,000
Real Estate Loans As Part Of Loan Portfolio
Concentration Risk [Line Items]
Concentration risk (as a percent)			71.00%		76.00%