Loans, Allowance for Loan Losses and Credit Quality (ALLL - by category) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Summary of changes in allowance for loan losses
Beginning Balance	$ 57,727	$ 54,995	$ 55,825	$ 55,100
Charge-offs	(1,143)	(1,165)	(2,257)	(3,788)
Recoveries	671	575	2,562	2,893
Provision for loan losses	950	800	2,075	1,000
Ending Balance	58,205	55,205	58,205	55,205
Ending Balance: Individually Evaluated for Impairment	1,893	2,090	1,893	2,090	$ 1,930
Ending Balance: Collectively Evaluated for Impairment	56,312	53,115	56,312	53,115
Commercial and Industrial [Member]
Summary of changes in allowance for loan losses
Beginning Balance	14,027	15,279	13,802	15,573
Charge-offs	(27)	(497)	(31)	(1,531)
Recoveries	63	22	850	903
Provision for loan losses	(189)	(518)	(747)	(659)
Ending Balance	13,874	14,286	13,874	14,286
Ending Balance: Individually Evaluated for Impairment	134	252	134	252	183
Ending Balance: Collectively Evaluated for Impairment	13,740	14,034	13,740	14,034
Commercial Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	29,011	26,359	27,327	25,873
Charge-offs	(341)	(28)	(365)	(236)
Recoveries	124	152	535	1,006
Provision for loan losses	609	582	1,906	422
Ending Balance	29,403	27,065	29,403	27,065
Ending Balance: Individually Evaluated for Impairment	355	225	355	225	204
Ending Balance: Collectively Evaluated for Impairment	29,048	26,840	29,048	26,840
Construction Loans [Member]
Summary of changes in allowance for loan losses
Beginning Balance	5,216	4,071	5,366	3,945
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	117	422	(33)	548
Ending Balance	5,333	4,493	5,333	4,493
Ending Balance: Individually Evaluated for Impairment	0	0	0	0
Ending Balance: Collectively Evaluated for Impairment	5,333	4,493	5,333	4,493
Small Business [Member]
Summary of changes in allowance for loan losses
Beginning Balance	1,441	1,248	1,264	1,171
Charge-offs	(98)	(2)	(191)	(198)
Recoveries	28	57	122	189
Provision for loan losses	113	(20)	289	121
Ending Balance	1,484	1,283	1,484	1,283
Ending Balance: Individually Evaluated for Impairment	2	28	2	28	4
Ending Balance: Collectively Evaluated for Impairment	1,482	1,255	1,482	1,255
Residential Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	2,578	2,551	2,590	2,834
Charge-offs	0	(40)	(27)	(242)
Recoveries	130	6	182	52
Provision for loan losses	(44)	75	(81)	(52)
Ending Balance	2,664	2,592	2,664	2,592
Ending Balance: Individually Evaluated for Impairment	1,156	1,313	1,156	1,313	1,278
Ending Balance: Collectively Evaluated for Impairment	1,508	1,279	1,508	1,279
Consumer Home Equity [Member]
Summary of changes in allowance for loan losses
Beginning Balance	4,986	4,871	4,889	4,956
Charge-offs	(154)	(249)	(491)	(659)
Recoveries	24	130	77	234
Provision for loan losses	196	128	577	349
Ending Balance	5,052	4,880	5,052	4,880
Ending Balance: Individually Evaluated for Impairment	223	245	223	245	238
Ending Balance: Collectively Evaluated for Impairment	4,829	4,635	4,829	4,635
Consumer Other [Member]
Summary of changes in allowance for loan losses
Beginning Balance	468	616	587	748
Charge-offs	(523)	(349)	(1,152)	(922)
Recoveries	302	208	796	509
Provision for loan losses	148	131	164	271
Ending Balance	395	606	395	606
Ending Balance: Individually Evaluated for Impairment	23	27	23	27	$ 23
Ending Balance: Collectively Evaluated for Impairment	$ 372	$ 579	$ 372	$ 579

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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