Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Allowance for loan losses [Roll Forward]
Beginning balance	$ 35,771	$ 37,133	$ 36,151	$ 35,933	$ 35,933
Provision charged to expense	1,543	666	4,418	4,659	7,521
Losses charged off	(2,828)	(2,443)	(8,331)	(7,123)	(11,085)
Recoveries	1,305	1,035	3,553	2,922	3,782
Ending balance	35,791	36,391	35,791	36,391	36,151
Ending balance [Abstract]
Individually evaluated for impairment	736	1,391	736	1,391	991
Collectively evaluated for impairment	35,055	35,000	35,055	35,000	35,160
Loans ending balance [Abstract]
Individually evaluated for impairment	46,883	46,199	46,883	46,199	47,412
Collectively evaluated for impairment	3,131,005	3,067,222	3,131,005	3,067,222	3,075,528
Commercial [Member] | Construction [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	740	669	686	884	884
Provision charged to expense	54	(19)	91	(239)	(237)
Losses charged off	0	(6)	0	(10)	(10)
Recoveries	23	28	40	37	49
Ending balance	817	672	817	672	686
Ending balance [Abstract]
Individually evaluated for impairment	0	25	0	25	25
Collectively evaluated for impairment	817	647	817	647	661
Loans ending balance [Abstract]
Individually evaluated for impairment	2,804	4,766	2,804	4,766	4,584
Collectively evaluated for impairment	78,668	69,516	78,668	69,516	71,895
Commercial [Member] | Real Estate [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	14,658	15,299	14,509	14,191	14,191
Provision charged to expense	298	(1)	895	1,622	2,281
Losses charged off	(460)	(249)	(937)	(776)	(2,038)
Recoveries	142	53	171	65	75
Ending balance	14,638	15,102	14,638	15,102	14,509
Ending balance [Abstract]
Individually evaluated for impairment	641	1,301	641	1,301	966
Collectively evaluated for impairment	13,997	13,801	13,997	13,801	13,543
Loans ending balance [Abstract]
Individually evaluated for impairment	33,612	29,240	33,612	29,240	31,465
Collectively evaluated for impairment	1,150,020	1,168,364	1,150,020	1,168,364	1,157,215
Commercial [Member] | Equipment Lease Financing [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	17	33	18	42	42
Provision charged to expense	(2)	(14)	(3)	(23)	(24)
Losses charged off	0	0	0	0	0
Recoveries	0	0	0	0	0
Ending balance	15	19	15	19	18
Ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	15	19	15	19	18
Loans ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	1,986	3,290	1,986	3,290	3,042
Commercial [Member] | Other [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	4,637	4,993	5,039	4,656	4,656
Provision charged to expense	82	210	98	1,229	1,744
Losses charged off	(521)	(549)	(1,078)	(1,386)	(1,893)
Recoveries	407	308	546	463	532
Ending balance	4,605	4,962	4,605	4,962	5,039
Ending balance [Abstract]
Individually evaluated for impairment	95	65	95	65	0
Collectively evaluated for impairment	4,510	4,897	4,510	4,897	5,039
Loans ending balance [Abstract]
Individually evaluated for impairment	8,589	10,124	8,589	10,124	9,481
Collectively evaluated for impairment	338,056	329,213	338,056	329,213	341,553
Residential [Member] | Construction [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	618	581	660	629	629
Provision charged to expense	(44)	49	(58)	0	31
Losses charged off	0	0	(28)	0	0
Recoveries	0	0	0	1	0
Ending balance	574	630	574	630	660
Ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	574	630	574	630	660
Loans ending balance [Abstract]
Individually evaluated for impairment	0	873	0	873	318
Collectively evaluated for impairment	61,782	63,568	61,782	63,568	67,040
Residential [Member] | Real Estate [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	5,234	5,662	5,688	6,027	6,027
Provision charged to expense	(566)	276	(625)	1	189
Losses charged off	(136)	(158)	(550)	(321)	(615)
Recoveries	7	6	26	79	87
Ending balance	4,539	5,786	4,539	5,786	5,688
Ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	4,539	5,786	4,539	5,786	5,688
Loans ending balance [Abstract]
Individually evaluated for impairment	1,878	1,196	1,878	1,196	1,564
Collectively evaluated for impairment	720,144	711,041	720,144	711,041	708,006
Residential [Member] | Home Equity [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	866	747	857	774	774
Provision charged to expense	(9)	113	18	87	257
Losses charged off	(19)	(53)	(38)	(57)	(178)
Recoveries	4	0	5	3	4
Ending balance	842	807	842	807	857
Ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	842	807	842	807	857
Loans ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	103,805	96,755	103,805	96,755	99,356
Consumer [Member] | Consumer Direct [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	1,910	1,866	1,863	1,885	1,885
Provision charged to expense	59	47	402	243	418
Losses charged off	(196)	(166)	(687)	(675)	(965)
Recoveries	133	110	328	404	525
Ending balance	1,906	1,857	1,906	1,857	1,863
Ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	1,906	1,857	1,906	1,857	1,863
Loans ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	146,002	137,657	146,002	137,657	137,754
Consumer [Member] | Consumer Indirect [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	7,091	7,283	6,831	6,845	6,845
Provision charged to expense	1,671	5	3,600	1,739	2,862
Losses charged off	(1,496)	(1,262)	(5,013)	(3,898)	(5,386)
Recoveries	589	530	2,437	1,870	2,510
Ending balance	7,855	6,556	7,855	6,556	6,831
Ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	7,855	6,556	7,855	6,556	6,831
Loans ending balance [Abstract]
Individually evaluated for impairment	0	0	0	0	0
Collectively evaluated for impairment	$ 530,542	$ 487,818	$ 530,542	$ 487,818	$ 489,667