Loans, Allowance for Loan Losses and Credit Quality (ALLL - by category) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Summary of changes in allowance for loan losses
Beginning Balance	$ 61,566	$ 55,825
Charge-offs	(508)	(537)
Recoveries	660	619
Provision for loan losses	600	525
Ending Balance	62,318	56,432
Ending Balance: Individually Evaluated for Impairment	5,055	2,507	$ 5,214
Ending Balance: Collectively Evaluated for Impairment	57,263	53,925
Commercial and Industrial [Member]
Summary of changes in allowance for loan losses
Beginning Balance	16,921	13,802
Charge-offs	0	(2)
Recoveries	187	138
Provision for loan losses	(590)	(453)
Ending Balance	16,518	13,485
Ending Balance: Individually Evaluated for Impairment	3,558	222	3,661
Ending Balance: Collectively Evaluated for Impairment	12,960	13,263
Commercial Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	30,369	27,327
Charge-offs	0	0
Recoveries	31	189
Provision for loan losses	343	1,079
Ending Balance	30,743	28,595
Ending Balance: Individually Evaluated for Impairment	173	802	196
Ending Balance: Collectively Evaluated for Impairment	30,570	27,793
Construction Loans [Member]
Summary of changes in allowance for loan losses
Beginning Balance	4,522	5,366
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	501	(266)
Ending Balance	5,023	5,100
Ending Balance: Individually Evaluated for Impairment	0	0
Ending Balance: Collectively Evaluated for Impairment	5,023	5,100
Small Business [Member]
Summary of changes in allowance for loan losses
Beginning Balance	1,502	1,264
Charge-offs	(70)	(63)
Recoveries	66	21
Provision for loan losses	35	119
Ending Balance	1,533	1,341
Ending Balance: Individually Evaluated for Impairment	2	3	8
Ending Balance: Collectively Evaluated for Impairment	1,531	1,338
Residential Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	2,621	2,590
Charge-offs	(23)	(19)
Recoveries	12	0
Provision for loan losses	106	(4)
Ending Balance	2,716	2,567
Ending Balance: Individually Evaluated for Impairment	1,066	1,223	1,086
Ending Balance: Collectively Evaluated for Impairment	1,650	1,344
Consumer Home Equity [Member]
Summary of changes in allowance for loan losses
Beginning Balance	5,238	4,889
Charge-offs	(14)	(147)
Recoveries	76	27
Provision for loan losses	45	146
Ending Balance	5,345	4,915
Ending Balance: Individually Evaluated for Impairment	235	231	242
Ending Balance: Collectively Evaluated for Impairment	5,110	4,684
Consumer Other [Member]
Summary of changes in allowance for loan losses
Beginning Balance	393	587
Charge-offs	(401)	(306)
Recoveries	288	244
Provision for loan losses	160	(96)
Ending Balance	440	429
Ending Balance: Individually Evaluated for Impairment	21	26	$ 21
Ending Balance: Collectively Evaluated for Impairment	$ 419	$ 403