Investment Securities (Schedule Of Securities With Gross Unrealized Losses Aggregated By Investment Category) (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Securities available for sale Less Than Twelve Months, Gross Unrealized Losses	$ (3,209)	$ (14,867)
Securities available for sale Less Than Twelve Months, Fair Value	371,578	730,836
Securities available for sale Over Twelve Months, Gross Unrealized Losses	(312)	(585)
Securities available for sale Over Twelve Months, Fair Value	17,746	20,908
Securities available for sale, Gross Unrealized Losses, Total	(3,521)	(15,452)
Securities available for sale, Fair Value, Total	389,324	751,744
Securities held to maturity Less Than Twelve Months, Gross Unrealized Losses	(274)	(1,594)
Securities held to maturity Less Than Twelve Months, Fair Value	19,907	43,721
Securities held to maturity Over Twelve Months, Gross Unrealized Losses	(104)	(202)
Securities held to maturity Over Twelve Months, Fair Value	1,225	1,128
Securities held to maturity, Gross Unrealized Losses, Total	(378)	(1,796)
Securities held to maturity, Fair Value, Total	21,132	44,849
US Treasury Securities [Member]
Securities available for sale Less Than Twelve Months, Gross Unrealized Losses	(7)
Securities available for sale Less Than Twelve Months, Fair Value	5,006
Securities available for sale, Gross Unrealized Losses, Total	(7)
Securities available for sale, Fair Value, Total	5,006
U.S. Government-Sponsored Enterprise Obligations [Member]
Securities available for sale Less Than Twelve Months, Gross Unrealized Losses	(1,032)	(3,794)
Securities available for sale Less Than Twelve Months, Fair Value	99,475	195,785
Securities available for sale, Gross Unrealized Losses, Total	(1,032)	(3,794)
Securities available for sale, Fair Value, Total	99,475	195,785
Securities held to maturity Less Than Twelve Months, Gross Unrealized Losses		(68)
Securities held to maturity Less Than Twelve Months, Fair Value		7,075
Securities held to maturity, Gross Unrealized Losses, Total		(68)
Securities held to maturity, Fair Value, Total		7,075
Obligations Of State And Political Subdivisions [Member]
Securities available for sale Less Than Twelve Months, Gross Unrealized Losses	(826)	(395)
Securities available for sale Less Than Twelve Months, Fair Value	17,821	6,771
Securities available for sale, Gross Unrealized Losses, Total	(826)	(395)
Securities available for sale, Fair Value, Total	17,821	6,771
Securities held to maturity Less Than Twelve Months, Gross Unrealized Losses	(274)	(1,526)
Securities held to maturity Less Than Twelve Months, Fair Value	19,907	36,646
Securities held to maturity Over Twelve Months, Gross Unrealized Losses	(104)	(202)
Securities held to maturity Over Twelve Months, Fair Value	1,225	1,128
Securities held to maturity, Gross Unrealized Losses, Total	(378)	(1,728)
Securities held to maturity, Fair Value, Total	21,132	37,774
Mortgage Backed Securities [Member]
Securities available for sale Less Than Twelve Months, Gross Unrealized Losses	(1,344)	(10,678)
Securities available for sale Less Than Twelve Months, Fair Value	249,276	528,280
Securities available for sale Over Twelve Months, Gross Unrealized Losses	(312)	(585)
Securities available for sale Over Twelve Months, Fair Value	17,746	20,908
Securities available for sale, Gross Unrealized Losses, Total	(1,656)	(11,263)
Securities available for sale, Fair Value, Total	267,022	549,188
Securities held to maturity Less Than Twelve Months, Gross Unrealized Losses
Securities held to maturity Less Than Twelve Months, Fair Value
Securities held to maturity Over Twelve Months, Gross Unrealized Losses
Securities held to maturity Over Twelve Months, Fair Value
Securities held to maturity, Gross Unrealized Losses, Total
Securities held to maturity, Fair Value, Total

This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for twelve months or longer for those securities which are categorized neither as held-to-maturity nor trading securities.

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This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for less than twelve months for those securities which are categorized neither as held-to-maturity nor trading securities.

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This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months.

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