Investment Securities (Schedule Of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	$ 991,373	$ 801,147
Securities Available-for-Sale, Gross Unrealized Holdings Gains	18,265	19,530
Securities Available-for-Sale, Gross Unrealized Holding Losses	2,157	32
Securities Available-for-Sale, Estimated Fair Value	1,007,481	820,645
Securities Held-to-Maturity, Amortized Cost	782,250	820,224
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	13,105	14,382
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	280	32
Securities Held-to-Maturity, Estimated Fair Value	795,075	834,574
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	599,125	370,043
Securities Available-for-Sale, Gross Unrealized Holdings Gains	478	1,614
Securities Available-for-Sale, Gross Unrealized Holding Losses	2,128
Securities Available-for-Sale, Estimated Fair Value	597,475	371,657
Obligations Of States And Political Subdivisions [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	2,616	2,616
Securities Available-for-Sale, Gross Unrealized Holdings Gains	39	44
Securities Available-for-Sale, Estimated Fair Value	2,655	2,660
Securities Held-to-Maturity, Amortized Cost	1,427	1,992
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	3	5
Securities Held-to-Maturity, Estimated Fair Value	1,430	1,997
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	388,444	427,300
Securities Available-for-Sale, Gross Unrealized Holdings Gains	16,734	16,995
Securities Available-for-Sale, Estimated Fair Value	405,178	444,295
Securities Held-to-Maturity, Amortized Cost	780,823	818,232
Securities Held-to-Maturity, Gross Unrecognized Holding Gains	13,102	14,377
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	280	32
Securities Held-to-Maturity, Estimated Fair Value	793,645	832,577
Other Equity Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	1,188	1,188
Securities Available-for-Sale, Gross Unrealized Holdings Gains	1,014	877
Securities Available-for-Sale, Gross Unrealized Holding Losses	29	32
Securities Available-for-Sale, Estimated Fair Value	$ 2,173	$ 2,033

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

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details

- Definition

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

+ References

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-Publisher AICPA

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+ Details

- Definition

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

+ References+ Details

- Definition

As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

+ References+ Details

- Definition

As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

+ References+ Details