Investments (Unrealized Losses) (Details) (USD $) In Thousands	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Investment securities available for sale, less than 12 months, fair value	$ 648,869	$ 9,156
Investment securities available for sale, 12 months or more, fair value	2,026	1,591
Investment securities available for sale, total fair value	650,895	10,747
Investment securities available for sale, less than 12 months, unrealized losses	1,592	104
Investment securities available for sale, 12 months or more, unrealized losses	50	25
Investment securities available for sale, total unrealized losses	1,642	129
Government Agency Securities [Member]
Investment securities available for sale, less than 12 months, fair value	507,210	4,005
Investment securities available for sale, 12 months or more, fair value
Investment securities available for sale, total fair value		4,005
Investment securities available for sale, less than 12 months, unrealized losses	1,140	23
Investment securities available for sale, 12 months or more, unrealized losses
Investment securities available for sale, total unrealized losses	1,140	23
Investment securities held to maturity, total fair value	507,210
U. S. Treasury [Member]
Investment securities available for sale, less than 12 months, fair value	50,307
Investment securities available for sale, 12 months or more, fair value
Investment securities available for sale, total fair value	50,307
Investment securities available for sale, less than 12 months, unrealized losses	5
Investment securities available for sale, 12 months or more, unrealized losses
Investment securities available for sale, total unrealized losses	5
Corporate Bonds [Member]
Investment securities available for sale, less than 12 months, fair value	9,957
Investment securities available for sale, less than 12 months, unrealized losses	43
Investment securities available for sale, total unrealized losses	43
Investment securities held to maturity, total fair value	9,957
Residential Mortgage-Backed Securities [Member]
Investment securities available for sale, less than 12 months, fair value	80,866	5,151
Investment securities available for sale, 12 months or more, fair value	2,016	1,152
Investment securities available for sale, total fair value	82,882	6,303
Investment securities available for sale, less than 12 months, unrealized losses	401	81
Investment securities available for sale, 12 months or more, unrealized losses	50	23
Investment securities available for sale, total unrealized losses	451	104
Investment securities held to maturity, less than 12 months, fair value
Investment securities held to maturity, 12 months or more, fair value	24	29
Investment securities held to maturity, total fair value	26	29
Investment securities held to maturity, less than 12 months, unrealized losses
Investment securities held to maturity, 12 months or more, unrealized losses	26	26
Investment securities held to maturity, total unrealized losses	24	26
State, County, Municipal [Member]
Investment securities available for sale, less than 12 months, fair value	529
Investment securities available for sale, 12 months or more, fair value	10	439
Investment securities available for sale, total fair value	539	439
Investment securities available for sale, less than 12 months, unrealized losses	3
Investment securities available for sale, 12 months or more, unrealized losses		2
Investment securities available for sale, total unrealized losses	$ 3	$ 2

This item represents the excess of [amortized] cost 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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 03-1
-Paragraph 21
-Subparagraph a(2)

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 17
-Subparagraph a(1)

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