Loans, Allowance for Loan Losses and Credit Quality (ALLL - by category) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Summary of changes in allowance for loan losses
Beginning Balance	$ 65,140	$ 60,862	$ 64,293	$ 60,643
Charge-offs	(472)	(569)	(1,031)	(1,162)
Recoveries	292	264	698	576
Provision for loan losses	1,000	2,000	2,000	2,500
Ending Balance	65,960	62,557	65,960	62,557
Ending Balance: Individually Evaluated for Impairment	1,073	1,187	1,073	1,187	$ 1,079
Ending Balance: Collectively Evaluated for Impairment	64,887	61,370	64,887	61,370
Commercial and Industrial [Member]
Summary of changes in allowance for loan losses
Beginning Balance	16,872	13,533	15,760	13,256
Charge-offs	0	(4)	0	(137)
Recoveries	0	59	124	71
Provision for loan losses	(15)	1,200	973	1,598
Ending Balance	16,857	14,788	16,857	14,788
Ending Balance: Individually Evaluated for Impairment	7	8	7	8	7
Ending Balance: Collectively Evaluated for Impairment	16,850	14,780	16,850	14,780
Commercial Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	32,049	31,459	32,370	31,453
Charge-offs	0	0	0	0
Recoveries	13	18	46	38
Provision for loan losses	598	618	244	604
Ending Balance	32,660	32,095	32,660	32,095
Ending Balance: Individually Evaluated for Impairment	74	74	74	74	37
Ending Balance: Collectively Evaluated for Impairment	32,586	32,021	32,586	32,021
Construction Loans [Member]
Summary of changes in allowance for loan losses
Beginning Balance	5,355	5,679	5,158	5,698
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for loan losses	238	(463)	435	(482)
Ending Balance	5,593	5,216	5,593	5,216
Ending Balance: Individually Evaluated for Impairment	0	0	0	0
Ending Balance: Collectively Evaluated for Impairment	5,593	5,216	5,593	5,216
Small Business [Member]
Summary of changes in allowance for loan losses
Beginning Balance	1,784	1,593	1,756	1,577
Charge-offs	(49)	(102)	(194)	(126)
Recoveries	20	10	47	19
Provision for loan losses	13	208	159	239
Ending Balance	1,768	1,709	1,768	1,709
Ending Balance: Individually Evaluated for Impairment	38	1	38	1	1
Ending Balance: Collectively Evaluated for Impairment	1,730	1,708	1,730	1,708
Residential Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	3,234	2,837	3,219	2,822
Charge-offs	0	(109)	0	(148)
Recoveries	0	1	1	3
Provision for loan losses	62	180	76	232
Ending Balance	3,296	2,909	3,296	2,909
Ending Balance: Individually Evaluated for Impairment	789	859	789	859	862
Ending Balance: Collectively Evaluated for Impairment	2,507	2,050	2,507	2,050
Consumer Home Equity [Member]
Summary of changes in allowance for loan losses
Beginning Balance	5,507	5,359	5,608	5,390
Charge-offs	(71)	(95)	(184)	(174)
Recoveries	18	23	84	57
Provision for loan losses	93	181	39	195
Ending Balance	5,547	5,468	5,547	5,468
Ending Balance: Individually Evaluated for Impairment	159	231	159	231	164
Ending Balance: Collectively Evaluated for Impairment	5,388	5,237	5,388	5,237
Consumer Other [Member]
Summary of changes in allowance for loan losses
Beginning Balance	339	402	422	447
Charge-offs	(352)	(259)	(653)	(577)
Recoveries	241	153	396	388
Provision for loan losses	11	76	74	114
Ending Balance	239	372	239	372
Ending Balance: Individually Evaluated for Impairment	6	14	6	14	$ 8
Ending Balance: Collectively Evaluated for Impairment	$ 233	$ 358	$ 233	$ 358