Investment Securities (Schedule Of Unrealized Loss On Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Securities Available-for-Sale, Less than 12 months, Fair value	$ 745,233	$ 860,016
Securities Available-for-Sale, Less than 12 months, Unrealized losses	6,321	11,778
Securities Available-for-Sale, 12 months or longer, Fair value	118,816	47,163
Securities Available-for-Sale, 12 months or longer, Unrealized losses	1,097	531
Securities Available-for-Sale, Fair value, Total	864,049	907,179
Securities Available-for-Sale, Unrealized losses, Total	7,418	12,309
Securities Held-to-Maturity, Less than 12 months, Fair value	116,083	134,909
Securities Held-to-Maturity, Less than 12 months, Unrealized losses	2,122	5,148
Securities Held-to-Maturity, 12 months or longer, Fair value	7,481	7,564
Securities Held-to-Maturity, 12 months or longer, Unrealized losses	24	87
Securities Held-to-Maturity, Fair value, Total	123,564	142,473
Securities Held-to-Maturity, Unrealized losses, Total	2,146	5,235
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Less than 12 months, Fair value	174,542	247,695
Securities Available-for-Sale, Less than 12 months, Unrealized losses	458	2,305
Securities Available-for-Sale, 12 months or longer, Fair value	94,144	19,838
Securities Available-for-Sale, 12 months or longer, Unrealized losses	856	162
Securities Available-for-Sale, Fair value, Total	268,686	267,533
Securities Available-for-Sale, Unrealized losses, Total	1,314	2,467
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Less than 12 months, Fair value	570,691	612,321
Securities Available-for-Sale, Less than 12 months, Unrealized losses	5,863	9,473
Securities Available-for-Sale, 12 months or longer, Fair value	24,672	27,325
Securities Available-for-Sale, 12 months or longer, Unrealized losses	241	369
Securities Available-for-Sale, Fair value, Total	595,363	639,646
Securities Available-for-Sale, Unrealized losses, Total	6,104	9,842
Securities Held-to-Maturity, 12 months or longer, Fair value	7,481	7,564
Securities Held-to-Maturity, 12 months or longer, Unrealized losses	24	87
Securities Held-to-Maturity, Fair value, Total	7,481	7,564
Securities Held-to-Maturity, Unrealized losses, Total	24	87
US States and Political Subdivisions Debt Securities [Member]
Schedule of Investments [Line Items]
Securities Held-to-Maturity, Less than 12 months, Fair value	116,083	134,909
Securities Held-to-Maturity, Less than 12 months, Unrealized losses	2,122	5,148
Securities Held-to-Maturity, 12 months or longer, Fair value	0
Securities Held-to-Maturity, 12 months or longer, Unrealized losses	0
Securities Held-to-Maturity, Fair value, Total	116,083	134,909
Securities Held-to-Maturity, Unrealized losses, Total	$ 2,122	$ 5,148

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 6
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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

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