Allowance for Loan Losses Allowance Rollforward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	$ 76,605	$ 82,286	$ 76,371	$ 84,057
Provision/ (credit) for loan losses	(5,000)	(2,000)	(6,200)	(2,000)
Financing Receivable, Allowance for Credit Losses, Charge-offs	(799)	(1,343)	(944)	(4,236)
Financing Receivable, Allowance for Credit Losses, Recoveries	3,741	1,857	5,320	2,979
Loans and Leases Receivable, Allowance at End of Period	74,547	80,800	74,547	80,800
Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	12,200	11,849	12,837	11,825
Provision/ (credit) for loan losses	357	(794)	(570)	(908)
Financing Receivable, Allowance for Credit Losses, Charge-offs	(285)	0	(334)	(27)
Financing Receivable, Allowance for Credit Losses, Recoveries	869	828	1,208	993
Loans and Leases Receivable, Allowance at End of Period	13,141	11,883	13,141	11,883
Commercial real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	46,366	50,466	44,979	52,497
Provision/ (credit) for loan losses	(4,323)	(1,628)	(3,266)	(2,547)
Financing Receivable, Allowance for Credit Losses, Charge-offs	(500)	(1,100)	(500)	(2,339)
Financing Receivable, Allowance for Credit Losses, Recoveries	2,543	1,006	2,873	1,133
Loans and Leases Receivable, Allowance at End of Period	44,086	48,744	44,086	48,744
Construction and land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	4,972	4,787	4,465	5,016
Provision/ (credit) for loan losses	(654)	213	(298)	(823)
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(100)	0	(100)
Financing Receivable, Allowance for Credit Losses, Recoveries	262	23	413	830
Loans and Leases Receivable, Allowance at End of Period	4,580	4,923	4,580	4,923
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	9,746	11,454	10,732	10,892
Provision/ (credit) for loan losses	(229)	311	(1,677)	2,138
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	(140)	(88)	(1,405)
Financing Receivable, Allowance for Credit Losses, Recoveries	52	0	602	0
Loans and Leases Receivable, Allowance at End of Period	9,569	11,625	9,569	11,625
Home equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	963	1,146	1,020	1,085
Provision/ (credit) for loan losses	14	55	(43)	453
Financing Receivable, Allowance for Credit Losses, Charge-offs	0	0	0	(360)
Financing Receivable, Allowance for Credit Losses, Recoveries	15	0	15	23
Loans and Leases Receivable, Allowance at End of Period	992	1,201	992	1,201
Consumer and other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	330	464	322	540
Provision/ (credit) for loan losses	(59)	(49)	(252)	(123)
Financing Receivable, Allowance for Credit Losses, Charge-offs	(14)	(3)	(22)	(5)
Financing Receivable, Allowance for Credit Losses, Recoveries	0	0	209	0
Loans and Leases Receivable, Allowance at End of Period	257	412	257	412
Unallocated Financing Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Allowance at Beginning of Period	2,028	2,120	2,016	2,202
Provision/ (credit) for loan losses	(106)	(108)	(94)	(190)
Loans and Leases Receivable, Allowance at End of Period	$ 1,922	$ 2,012	$ 1,922	$ 2,012