Investment Securities (Schedule Of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	$ 1,251,451	$ 1,299,980
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	18,605	15,010
Securities Available-for-Sale, Gross Unrealized Holding Losses	4,579	13,075
Securities Available-for-Sale, Total Fair value	1,265,477us-gaap_AvailableForSaleSecurities	1,301,915us-gaap_AvailableForSaleSecurities
Securities Held-to-Maturity, Amortized Cost	133,383us-gaap_HeldToMaturitySecurities	140,562us-gaap_HeldToMaturitySecurities
Securities Held-to-Maturity, Estimated Fair Value	136,418	143,490
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	496,887	546,886
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	570	11
Securities Available-for-Sale, Gross Unrealized Holding Losses	2,286	8,833
Securities Available-for-Sale, Total Fair value	495,171	538,064
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	753,444	751,974
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	16,525	13,421
Securities Available-for-Sale, Gross Unrealized Holding Losses	2,293	4,242
Securities Available-for-Sale, Total Fair value	767,676	761,153
Securities Held-to-Maturity, Amortized Cost	133,383	140,562
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	3,118	3,088
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	83	160
Securities Held-to-Maturity, Estimated Fair Value	136,418	143,490
Other Equity Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	1,120	1,120
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,510	1,578
Securities Available-for-Sale, Total Fair value	$ 2,630	$ 2,698

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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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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Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity in a continuous loss position.

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

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