Loans, Allowance for Loan Losses and Credit Quality (ALLL - by category) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Summary of changes in allowance for loan losses
Beginning Balance	$ 62,318	$ 56,432	$ 61,566	$ 55,825
Charge-offs	(4,198)	(577)	(4,706)	(1,114)
Recoveries	309	1,272	969	1,891
Provision for loan losses	1,050	600	1,650	1,125
Ending Balance	59,479	57,727	59,479	57,727
Ending Balance: Individually Evaluated for Impairment	1,536	2,492	1,536	2,492	$ 5,214
Ending Balance: Collectively Evaluated for Impairment	57,943	55,235	57,943	55,235
Commercial and Industrial [Member]
Summary of changes in allowance for loan losses
Beginning Balance	16,518	13,485	16,921	13,802
Charge-offs	(3,591)	(2)	(3,591)	(4)
Recoveries	13	649	200	787
Provision for loan losses	604	(105)	14	(558)
Ending Balance	13,544	14,027	13,544	14,027
Ending Balance: Individually Evaluated for Impairment	70	255	70	255	3,661
Ending Balance: Collectively Evaluated for Impairment	13,474	13,772	13,474	13,772
Commercial Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	30,743	28,595	30,369	27,327
Charge-offs	0	(25)	0	(25)
Recoveries	26	223	57	412
Provision for loan losses	178	218	521	1,297
Ending Balance	30,947	29,011	30,947	29,011
Ending Balance: Individually Evaluated for Impairment	166	791	166	791	196
Ending Balance: Collectively Evaluated for Impairment	30,781	28,220	30,781	28,220
Construction Loans [Member]
Summary of changes in allowance for loan losses
Beginning Balance	5,023	5,100	4,522	5,366
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	(209)	116	292	(150)
Ending Balance	4,814	5,216	4,814	5,216
Ending Balance: Individually Evaluated for Impairment	0	0	0	0
Ending Balance: Collectively Evaluated for Impairment	4,814	5,216	4,814	5,216
Small Business [Member]
Summary of changes in allowance for loan losses
Beginning Balance	1,533	1,341	1,502	1,264
Charge-offs	(24)	(30)	(94)	(93)
Recoveries	13	73	79	94
Provision for loan losses	91	57	126	176
Ending Balance	1,613	1,441	1,613	1,441
Ending Balance: Individually Evaluated for Impairment	1	3	1	3	8
Ending Balance: Collectively Evaluated for Impairment	1,612	1,438	1,612	1,438
Residential Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	2,716	2,567	2,621	2,590
Charge-offs	(116)	(8)	(139)	(27)
Recoveries	2	51	14	51
Provision for loan losses	91	(32)	197	(36)
Ending Balance	2,693	2,578	2,693	2,578
Ending Balance: Individually Evaluated for Impairment	1,036	1,188	1,036	1,188	1,086
Ending Balance: Collectively Evaluated for Impairment	1,657	1,390	1,657	1,390
Consumer Home Equity [Member]
Summary of changes in allowance for loan losses
Beginning Balance	5,345	4,915	5,238	4,889
Charge-offs	(122)	(190)	(136)	(337)
Recoveries	26	26	102	53
Provision for loan losses	104	235	149	381
Ending Balance	5,353	4,986	5,353	4,986
Ending Balance: Individually Evaluated for Impairment	243	228	243	228	242
Ending Balance: Collectively Evaluated for Impairment	5,110	4,758	5,110	4,758
Consumer Other [Member]
Summary of changes in allowance for loan losses
Beginning Balance	440	429	393	587
Charge-offs	(345)	(322)	(746)	(628)
Recoveries	229	250	517	494
Provision for loan losses	191	111	351	15
Ending Balance	515	468	515	468
Ending Balance: Individually Evaluated for Impairment	20	27	20	27	$ 21
Ending Balance: Collectively Evaluated for Impairment	$ 495	$ 441	$ 495	$ 441