Securities (Schedule Of Amortized Cost And Fair Value Of Securities Available For Sale) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	$ 1,109,779	$ 645,658
Securities Available For Sale, Gross Unrealized Gains	18,213	9,829
Securities Available For Sale, Gross Unrealized Loss	(15,153)	(14,916)
Securities Available For Sale, Fair Value	1,112,839	640,571
U.S. Treasury And Other U.S. Government Agencies And Corporations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	325,453	231,187
Securities Available For Sale, Gross Unrealized Gains	1,852	642
Securities Available For Sale, Fair Value	327,305	231,829
Agency Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	287,926	166,758
Securities Available For Sale, Gross Unrealized Gains	9,255	4,853
Securities Available For Sale, Fair Value	297,181	171,611
Agency Collateralized Mortgage obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	406,741	181,493
Securities Available For Sale, Gross Unrealized Gains	4,248	2,236
Securities Available For Sale, Gross Unrealized Loss	(114)
Securities Available For Sale, Fair Value	410,875	183,729
Non-Agency Collateralized Mortgage obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	2,950	31
Securities Available For Sale, Gross Unrealized Gains	41
Securities Available For Sale, Gross Unrealized Loss		(1)
Securities Available For Sale, Fair Value	2,991	30
States Of The U.S. And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	27,091	38,509
Securities Available For Sale, Gross Unrealized Gains	1,463	1,841
Securities Available For Sale, Fair Value	28,554	40,350
Collateralized Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	34,264	19,224
Securities Available For Sale, Gross Unrealized Gains	156
Securities Available For Sale, Gross Unrealized Loss	(13,720)	(13,226)
Securities Available For Sale, Fair Value	20,700	5,998
Other Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	23,799	6,863
Securities Available For Sale, Gross Unrealized Gains	756
Securities Available For Sale, Gross Unrealized Loss	(1,295)	(1,666)
Securities Available For Sale, Fair Value	23,260	5,197
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	1,108,224	644,065
Securities Available For Sale, Gross Unrealized Gains	17,771	9,572
Securities Available For Sale, Gross Unrealized Loss	(15,129)	(14,893)
Securities Available For Sale, Fair Value	1,110,866	638,744
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	1,555	1,593
Securities Available For Sale, Gross Unrealized Gains	442	257
Securities Available For Sale, Gross Unrealized Loss	(24)	(23)
Securities Available For Sale, Fair Value	$ 1,973	$ 1,827

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

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-Publisher FASB

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Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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Reference 10: http://www.xbrl.org/2003/role/presentationRef

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-Name Statement of Financial Accounting Standard (FAS)

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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