Allowance for Loan Losses Allowance Rollforward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	$ 97,902	$ 100,282	$ 96,114	$ 98,403
Provision/ (Credit) for loan losses	1,700	(2,190)	5,700	11,160
Financing Receivable, Allowance for Credit Losses, Charge-offs	(4,368)	(4,928)	(7,309)	(17,994)
Financing Receivable, Allowance for Credit Losses, Recoveries	3,820	5,578	4,549	7,173
Loans and Leases Receivable, Allowance at End of Period	99,054	98,742	99,054	98,742
Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	12,062	13,864	12,163	13,438
Provision/ (Credit) for loan losses	1,278	(1,080)	3,105	(205)
Financing Receivable, Allowance for Credit Losses, Charge-offs	(358)	(1,246)	(2,669)	(2,052)
Financing Receivable, Allowance for Credit Losses, Recoveries	261	922	644	1,279
Loans and Leases Receivable, Allowance at End of Period	13,243	12,460	13,243	12,460
Commercial real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	65,366	68,293	63,625	65,760
Provision/ (Credit) for loan losses	(1,142)	(753)	888	11,158
Financing Receivable, Allowance for Credit Losses, Charge-offs	(2,861)	(1,673)	(3,267)	(11,919)
Financing Receivable, Allowance for Credit Losses, Recoveries	3,214	1,047	3,331	1,915
Loans and Leases Receivable, Allowance at End of Period	64,577	66,914	64,577	66,914
Construction and land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	5,836	5,887	6,382	6,875
Provision/ (Credit) for loan losses	(17)	(2,877)	(729)	(2,595)
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(602)	0	(2,230)
Financing Receivable, Allowance for Credit Losses, Recoveries	344	3,596	510	3,954
Loans and Leases Receivable, Allowance at End of Period	6,163	6,004	6,163	6,004
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	10,054	7,873	9,286	7,449
Provision/ (Credit) for loan losses	1,873	1,476	2,839	2,095
Financing Receivable, Allowance for Credit Losses, Charge-offs	(1,083)	(850)	(1,281)	(1,045)
Financing Receivable, Allowance for Credit Losses, Recoveries	0	0	0	0
Loans and Leases Receivable, Allowance at End of Period	10,844	8,499	10,844	8,499
Home equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	1,543	1,199	1,535	1,231
Provision/ (Credit) for loan losses	(54)	186	(107)	153
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(95)	0	(95)
Financing Receivable, Allowance for Credit Losses, Recoveries	0	1	61	2
Loans and Leases Receivable, Allowance at End of Period	1,489	1,291	1,489	1,291
Consumer and other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	1,009	1,463	1,149	1,478
Provision/ (Credit) for loan losses	(204)	603	(320)	768
Financing Receivable, Allowance for Credit Losses, Charge-offs	(66)	(462)	(92)	(653)
Financing Receivable, Allowance for Credit Losses, Recoveries	1	12	3	23
Loans and Leases Receivable, Allowance at End of Period	740	1,616	740	1,616
Unallocated Financing Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	2,032	1,703	1,974	2,172
Provision/ (Credit) for loan losses	(34)	255	24	(214)
Loans and Leases Receivable, Allowance at End of Period	$ 1,998	$ 1,958	$ 1,998	$ 1,958