Investment Securities (Schedule Of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	$ 1,166,888	$ 1,099,658
Securities Available-for-Sale, Gross Unrealized Holdings Gains	11,818	16,523
Securities Available-for-Sale, Gross Unrealized Holding Losses	49,223	1,727
Securities Available-for-Sale, Total Fair value	1,129,483	1,114,454
Securities Held-to-Maturity, Amortized Cost	193,997	401,390
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	5,959	9,353
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	15	38
Securities Held-to-Maturity, Estimated Fair Value	199,941	410,705
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	645,631	695,655
Securities Available-for-Sale, Gross Unrealized Holdings Gains	115	1,352
Securities Available-for-Sale, Gross Unrealized Holding Losses	40,001	1,280
Securities Available-for-Sale, Total Fair value	605,745	695,727
Obligations Of States And Political Subdivisions [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	220	984
Securities Available-for-Sale, Gross Unrealized Holdings Gains	1	19
Securities Available-for-Sale, Gross Unrealized Holding Losses
Securities Available-for-Sale, Total Fair value	221	1,003
Securities Held-to-Maturity, Amortized Cost	240	570
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	1	2
Securities Held-to-Maturity, Gross Unrecognized Holding Losses
Securities Held-to-Maturity, Estimated Fair Value	241	572
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	519,917	401,882
Securities Available-for-Sale, Gross Unrealized Holdings Gains	10,330	14,067
Securities Available-for-Sale, Gross Unrealized Holding Losses	9,222	447
Securities Available-for-Sale, Total Fair value	521,025	415,502
Securities Held-to-Maturity, Amortized Cost	193,757	400,820
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	5,958	9,351
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	15	38
Securities Held-to-Maturity, Estimated Fair Value	199,700	410,133
Other Equity Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	1,120	1,137
Securities Available-for-Sale, Gross Unrealized Holdings Gains	1,372	1,085
Securities Available-for-Sale, Gross Unrealized Holding Losses
Securities Available-for-Sale, Total Fair value	$ 2,492	$ 2,222

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

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