Loans (Narrative) (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Partial charge-offs on impaired loans		$ 107,200,000	$ 103,800,000
Allowance for loan losses individually evaluated for impairment	10,946,000	10,946,000	15,935,000
Recorded investment, related to loans	36,100,000	36,100,000	52,700,000
TDRs included in nonaccrual loan totals	102,400,000	102,400,000	100,400,000
TDRs included in accruing loan totals	27,300,000	27,300,000	28,700,000
Nonaccrual TDRs considered current	68,400,000	68,400,000	79,900,000
Commitments to lend additional funds to borrowers whose terms had been modified in a TDR	3,500,000	3,500,000	4,000,000
Specific reserves related to troubled debt restructuring	7,400,000	7,400,000	9,100,000
Additional specific reserves related to troubled debt restructurings	818,000	1,100,000
Modified substandard commercial loans, total recorded investment	1,200,000	1,200,000
Modified substandard consumer loans, total recorded investment	16,000,000	16,000,000
Loan Modifications on Nonacrrual status	2,200,000	8,000,000
Recorded investment	17,000,000	17,000,000
Financing Receivable With No Related Allowance Recorded [Member]
Financing Receivable, Recorded Investment [Line Items]
Partial charge-offs on impaired loans		99,900,000	83,700,000
Financing Receivable With A Related Allowance Recorded [Member]
Financing Receivable, Recorded Investment [Line Items]
Partial charge-offs on impaired loans		7,300,000	20,100,000
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Allowance for loan losses individually evaluated for impairment	1,354,000	1,354,000	4,431,000
Accruing [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment	110,000	110,000
Nonaccrual [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment	$ 16,900,000	$ 16,900,000