Investment Securities (Schedule Of Unrealized Loss On Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Securities Available-for-Sale, Less than 12 months, Fair value	$ 251,414	$ 506,280
Securities Available-for-Sale, Less than 12 months, Unrealized losses	1,095	5,998
Securities Available-for-Sale, 12 months or longer, Fair value	181,807	449,569
Securities Available-for-Sale, 12 months or longer, Unrealized losses	5,365	19,917
Securities Available-for-Sale, Fair value, Total	433,221	955,849
Securities Available-for-Sale, Unrealized losses, Total	6,460	25,915
Securities Held-to-Maturity, Less than 12 months, Fair value		124,616
Securities Held-to-Maturity, Less than 12 months, Unrealized losses		1,933
Securities Held-to-Maturity, 12 months or longer, Fair value		77,654
Securities Held-to-Maturity, 12 months or longer, Unrealized losses		1,742
Securities Held-to-Maturity, Fair value, Total		202,270
Securities Held-to-Maturity, Unrealized losses, Total		3,675
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Less than 12 months, Fair value	251,414	506,280
Securities Available-for-Sale, Less than 12 months, Unrealized losses	1,095	5,998
Securities Available-for-Sale, 12 months or longer, Fair value	181,807	449,569
Securities Available-for-Sale, 12 months or longer, Unrealized losses	5,365	19,917
Securities Available-for-Sale, Fair value, Total	433,221	955,849
Securities Available-for-Sale, Unrealized losses, Total	$ 6,460	25,915
Securities Held-to-Maturity, Less than 12 months, Fair value		32,656
Securities Held-to-Maturity, Less than 12 months, Unrealized losses		838
Securities Held-to-Maturity, 12 months or longer, Fair value		6,931
Securities Held-to-Maturity, 12 months or longer, Unrealized losses		165
Securities Held-to-Maturity, Fair value, Total		39,587
Securities Held-to-Maturity, Unrealized losses, Total		1,003
US States and Political Subdivisions Debt Securities [Member]
Schedule of Investments [Line Items]
Securities Held-to-Maturity, Less than 12 months, Fair value		91,960
Securities Held-to-Maturity, Less than 12 months, Unrealized losses		1,095
Securities Held-to-Maturity, 12 months or longer, Fair value		70,723
Securities Held-to-Maturity, 12 months or longer, Unrealized losses		1,577
Securities Held-to-Maturity, Fair value, Total		162,683
Securities Held-to-Maturity, Unrealized losses, Total		$ 2,672

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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