Investment Securities (Schedule Of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2014	Dec. 31, 2013
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	$ 1,215,422	$ 1,222,143
Securities Available-for-Sale, Gross Unrealized Holdings Gains	10,642	9,609
Securities Available-for-Sale, Gross Unrealized Holding Losses	39,687	55,486
Securities Available-for-Sale, Total Fair value	1,186,377	1,176,266
Securities Held-to-Maturity, Amortized Cost	171,936	182,061
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	3,936	5,383
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	495	42
Securities Held-to-Maturity, Estimated Fair Value	175,377	187,402
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	570,633	570,632
Securities Available-for-Sale, Gross Unrealized Holdings Gains
Securities Available-for-Sale, Gross Unrealized Holding Losses	31,617	45,496
Securities Available-for-Sale, Total Fair value	539,016	525,136
Obligations Of States And Political Subdivisions [Member]
Schedule of Investments [Line Items]
Securities Held-to-Maturity, Amortized Cost	155	240
Securities Held-to-Maturity, Gross Unrecognized Holding Gains		1
Securities Held-to-Maturity, Gross Unrecognized Holding Losses
Securities Held-to-Maturity, Estimated Fair Value	155	241
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	643,669	650,391
Securities Available-for-Sale, Gross Unrealized Holdings Gains	9,074	8,070
Securities Available-for-Sale, Gross Unrealized Holding Losses	8,070	9,990
Securities Available-for-Sale, Total Fair value	644,673	648,471
Securities Held-to-Maturity, Amortized Cost	171,781	181,821
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	3,936	5,382
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	495	42
Securities Held-to-Maturity, Estimated Fair Value	175,222	187,161
Other Equity Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	1,120	1,120
Securities Available-for-Sale, Gross Unrealized Holdings Gains	1,568	1,539
Securities Available-for-Sale, Gross Unrealized Holding Losses
Securities Available-for-Sale, Total Fair value	$ 2,688	$ 2,659

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of investments in debt securities classified as held-to-maturity.

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Amount of unrecognized gain before loss on investments in held-to-maturity securities.

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Amount of unrecognized loss before gain on investments in held-to-maturity securities. Excludes write-down for other than temporary impairment (OTTI).

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