Financial Instruments With Off-Balance-Sheet Risk And Concentrations Of Credit Risk (Schedule Of Contract Amounts And Maturity Term Of Credit Commitment) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 2,344,466	$ 1,684,649
Commitments To Extend Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	2,340,954	1,683,499
Standby Letters Of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 3,512	$ 1,150