Securities (Schedule Of Amortized Cost And Fair Value Of Securities Available For Sale) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	$ 1,163,457	$ 1,170,439
Securities Available For Sale, Gross Unrealized Gains	15,402	16,858
Securities Available For Sale, Gross Unrealized Loss	(14,532)	(14,614)
Securities Available For Sale, Fair Value	1,164,327	1,172,683
U.S. Government-Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	353,703	352,910
Securities Available For Sale, Gross Unrealized Gains	1,240	1,676
Securities Available For Sale, Gross Unrealized Loss	(125)	(129)
Securities Available For Sale, Fair Value	354,818	354,457
Agency Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	227,465	267,575
Securities Available For Sale, Gross Unrealized Gains	6,823	7,575
Securities Available For Sale, Gross Unrealized Loss
Securities Available For Sale, Fair Value	234,288	275,150
Agency Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	500,955	465,574
Securities Available For Sale, Gross Unrealized Gains	4,072	4,201
Securities Available For Sale, Gross Unrealized Loss	(692)	(228)
Securities Available For Sale, Fair Value	504,335	469,547
Non-Agency Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	2,386	2,679
Securities Available For Sale, Gross Unrealized Gains	27	50
Securities Available For Sale, Gross Unrealized Loss
Securities Available For Sale, Fair Value	2,413	2,729
States Of The U.S. And Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	20,382	23,592
Securities Available For Sale, Gross Unrealized Gains	1,045	1,232
Securities Available For Sale, Gross Unrealized Loss
Securities Available For Sale, Fair Value	21,427	24,824
Collateralized Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	35,226	34,765
Securities Available For Sale, Gross Unrealized Gains	888	967
Securities Available For Sale, Gross Unrealized Loss	(12,785)	(13,276)
Securities Available For Sale, Fair Value	23,329	22,456
Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	21,786	21,790
Securities Available For Sale, Gross Unrealized Gains	764	695
Securities Available For Sale, Gross Unrealized Loss	(907)	(972)
Securities Available For Sale, Fair Value	21,643	21,513
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	1,161,903	1,168,885
Securities Available For Sale, Gross Unrealized Gains	14,859	16,396
Securities Available For Sale, Gross Unrealized Loss	(14,509)	(14,605)
Securities Available For Sale, Fair Value	1,162,253	1,170,676
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available For Sale, Amortized Cost	1,554	1,554
Securities Available For Sale, Gross Unrealized Gains	543	462
Securities Available For Sale, Gross Unrealized Loss	(23)	(9)
Securities Available For Sale, Fair Value	$ 2,074	$ 2,007

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

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-Name FASB Staff Position (FSP)

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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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

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

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

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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