Investment Securities (Amortized Cost And Estimated Fair Value Of Investment Securities Available For Sale) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 349,581	$ 330,060	$ 330,917
Gross Unrealized Gains	12,458	10,551	10,583
Gross Unrealized Losses	(988)	(644)	(661)
Fair Value	361,051	339,967	340,839
U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,606	14,670	20,007
Gross Unrealized Gains	289	267	302
Fair Value	8,895	14,937	20,309
State, county and municipal securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	106,541	75,665	68,486
Gross Unrealized Gains	5,345	3,558	3,196
Gross Unrealized Losses	(144)	(90)
Fair Value	111,742	79,133	71,682
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,793	11,640	11,638
Gross Unrealized Gains	262	167	247
Gross Unrealized Losses	(560)	(406)	(357)
Fair Value	11,495	11,401	11,528
Mortgage backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	222,641	228,085	230,786
Gross Unrealized Gains	6,562	6,559	6,838
Gross Unrealized Losses	(284)	(148)	(304)
Fair Value	$ 228,919	$ 234,496	$ 237,320

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

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

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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