Investment Securities (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Schedule of Investments [Line Items]
Proceeds from Sale of Available-for-sale Securities			$ 22,395	$ 28,272
Available-for-sale Securities Pledged as Collateral	186,036		186,036		158,189
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax	(13)	(11)	167	(7)
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	57		57		36
Book value	416,738		416,738		341,023
Fair value	425,215		425,215		348,091
Pooled trust preferred securities [Member]
Schedule of Investments [Line Items]
Available-for-sale Securities, number	seven		seven
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	5		5		5
Book value	3,519		3,519		3,640
Fair value	$ 1,961		$ 1,961		$ 1,929
Pooled trust preferred securities [Member] | More than 12 Months [Member]
Schedule of Investments [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	5		5