Investment Securities (Schedule Of Investment Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 1,080,988	$ 1,007,834
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	40,654	52,235
Securities Available-for-Sale, Gross Unrealized Holding Losses	6,358	728
Debt Securities, Available-for-sale	1,115,284	1,059,341
US States and Political Subdivisions Debt Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	278,676	279,245
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	19,637	25,973
Debt Securities, Available-for-sale	298,313	305,218
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	800,312	726,589
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	20,955	26,248
Securities Available-for-Sale, Gross Unrealized Holding Losses	6,358	728
Debt Securities, Available-for-sale	814,909	752,109
Corporate Debt Securities
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,000	2,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	62	14
Debt Securities, Available-for-sale	$ 2,062	$ 2,014

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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