Long Term Subordinated Notes (Schedule Of Outstanding Fixed To Floating Rate Long Term Subordinated Notes) (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Consolidated Balance Sheet Amount	$ 236,758,000	$ 236,659,000
Subordinated Notes 6.6% [Member] \| Long Term Subordinated Debt [Member]
Debt Instrument [Line Items]
Date Issued	Apr. 26, 2007
Original Principal Amount	$ 400,000,000
Maturity date	May 01, 2067
Consolidated Balance Sheet Amount	$ 236,758,000	236,659,000
Market value	$ 233,191,000	$ 200,390,000
Subordinated Notes 6.6% [Member] \| Long Term Subordinated Debt [Member] \| Scheduled [Member]
Debt Instrument [Line Items]
Maturity date	May 15, 2037

Face (par) amount of debt instrument at time of issuance.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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-Publisher FASB
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Date the debt instrument was issued, in CCYY-MM-DD format.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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