Loans (Impaired Loans) (Details) (USD $)	3 Months Ended					6 Months Ended
	Jun. 30, 2012		Dec. 31, 2011		Jun. 30, 2011	Jun. 30, 2012		Jun. 30, 2011
Financing Receivable, Impaired [Line Items]
Impaired loans, held for sale	$ 0		$ 4,529,000			$ 0
Impaired loans, no individually reviewed for impairment	6,750,000		5,127,000			6,750,000
Impaired loans, individually reviewed, with no impairment	55,160,000		53,884,000			55,160,000
Impaired loans, individually reviewed, with impairment	40,778,000		42,357,000			40,778,000
Total impaired loans, excluding purchased impaired	102,688,000	[1]	105,897,000	[1]		102,688,000	[1]
Purchased impaired loans with subsequent deterioration	36,659,000		0			36,659,000
Purchased impaired loans with no subsequent deterioration	250,433,000		330,836,000			250,433,000
Impaired loan, individually reviewed, with impairment, associated reserves	8,724,000	[1]	11,090,000	[1]		8,724,000	[1]
Purchased impaired loans with subsequent deterioration, associated reserves	3,336,000		0			3,336,000
Total reserves	12,060,000		11,090,000			12,060,000
Average impaired loans calculated using a simple average	107,263,000		112,600,000		259,607,000	106,815,000		291,741,000
Restructured loans	27,300,000		28,300,000			27,300,000
Performing [Member]
Financing Receivable, Impaired [Line Items]
Restructured loans	3,900,000		2,900,000			3,900,000
Special Mention [Member]
Financing Receivable, Impaired [Line Items]
Loan balance	$ 91,700,000		$ 130,700,000			$ 91,700,000

[1] Included at June 30, 2012 and December 31, 2011 were $3.9 million and $2.9 million, respectively, in restructured and performing loans.