Allowance for Loan Losses Allowance Rollforward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	$ 76,371	$ 84,057
Provision/ (credit) for loan losses	(1,200)	0
Financing Receivable, Allowance for Credit Losses, Charge-offs	(145)	(2,893)
Financing Receivable, Allowance for Credit Losses, Recoveries	1,579	1,122
Loans and Leases Receivable, Allowance at End of Period	76,605	82,286
Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	12,837	11,825
Provision/ (credit) for loan losses	(927)	(114)
Financing Receivable, Allowance for Credit Losses, Charge-offs	(49)	(27)
Financing Receivable, Allowance for Credit Losses, Recoveries	339	165
Loans and Leases Receivable, Allowance at End of Period	12,200	11,849
Commercial real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	44,979	52,497
Provision/ (credit) for loan losses	1,057	(919)
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(1,239)
Financing Receivable, Allowance for Credit Losses, Recoveries	330	127
Loans and Leases Receivable, Allowance at End of Period	46,366	50,466
Construction and land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	4,465	5,016
Provision/ (credit) for loan losses	356	(1,036)
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	0
Financing Receivable, Allowance for Credit Losses, Recoveries	151	807
Loans and Leases Receivable, Allowance at End of Period	4,972	4,787
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	10,732	10,892
Provision/ (credit) for loan losses	(1,448)	1,827
Financing Receivable, Allowance for Credit Losses, Charge-offs	(88)	(1,265)
Financing Receivable, Allowance for Credit Losses, Recoveries	550	0
Loans and Leases Receivable, Allowance at End of Period	9,746	11,454
Home equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	1,020	1,085
Provision/ (credit) for loan losses	(57)	398
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(360)
Financing Receivable, Allowance for Credit Losses, Recoveries	0	23
Loans and Leases Receivable, Allowance at End of Period	963	1,146
Consumer and other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	322	540
Provision/ (credit) for loan losses	(193)	(74)
Financing Receivable, Allowance for Credit Losses, Charge-offs	(8)	(2)
Financing Receivable, Allowance for Credit Losses, Recoveries	209	0
Loans and Leases Receivable, Allowance at End of Period	330	464
Unallocated Financing Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	2,016	2,202
Provision/ (credit) for loan losses	12	(82)
Loans and Leases Receivable, Allowance at End of Period	$ 2,028	$ 2,120