Impaired Loan Information by Portfolio (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	$ 1,079	$ 1,342	$ 5,214
Related Allowance	1,079	1,342	5,214
Recorded Investment	59,060	72,801	77,297
Unpaid Principal Balance	68,514	79,276	81,071
Average Recorded Investment	63,522	76,180	77,209
Interest Income Recognized	1,554	2,026	2,700
Commercial and Industrial [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	7	10	3,661
Commercial Real Estate [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	37	42	196
Construction Loans [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0	0	0
Small Business [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	1	1	8
Residential Real Estate [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	862	1,007	1,086
Home Equity [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	164	265	242
Consumer Portfolio Segment [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	8	17	21
With No Related Allowance Recorded [Member]
Impaired loans by loan portfolio
Recorded Investment	47,900	57,373	49,745
Unpaid Principal Balance	56,125	62,867	52,377
Average Recorded Investment	51,970	60,380	48,814
Interest Income Recognized	1,111	1,449	1,764
Related Allowance	0	0	0
With No Related Allowance Recorded [Member] \| Commercial and Industrial [Member]
Impaired loans by loan portfolio
Recorded Investment	28,459	34,267	28,776
Unpaid Principal Balance	35,913	38,329	29,772
Average Recorded Investment	31,117	36,631	26,472
Interest Income Recognized	142	446	927
Related Allowance	0	0	0
With No Related Allowance Recorded [Member] \| Commercial Real Estate [Member]
Impaired loans by loan portfolio
Recorded Investment	9,552	13,245	11,628
Unpaid Principal Balance	9,832	14,374	12,891
Average Recorded Investment	10,561	13,683	12,744
Interest Income Recognized	519	559	437
Related Allowance	0	0	0
With No Related Allowance Recorded [Member] \| Construction Loans [Member]
Impaired loans by loan portfolio
Related Allowance			0
With No Related Allowance Recorded [Member] \| Small Business [Member]
Impaired loans by loan portfolio
Recorded Investment	358	556	494
Unpaid Principal Balance	439	619	569
Average Recorded Investment	401	569	534
Interest Income Recognized	14	21	20
Related Allowance	0	0	0
With No Related Allowance Recorded [Member] \| Residential Real Estate [Member]
Impaired loans by loan portfolio
Recorded Investment	4,518	4,264	4,216
Unpaid Principal Balance	4,686	4,397	4,427
Average Recorded Investment	4,597	4,332	4,302
Interest Income Recognized	212	218	185
Related Allowance	0	0	0
With No Related Allowance Recorded [Member] \| Home Equity [Member]
Impaired loans by loan portfolio
Recorded Investment	4,957	4,950	4,485
Unpaid Principal Balance	5,199	5,056	4,572
Average Recorded Investment	5,230	5,063	4,602
Interest Income Recognized	220	198	184
Related Allowance	0	0	0
With No Related Allowance Recorded [Member] \| Consumer Portfolio Segment [Member]
Impaired loans by loan portfolio
Recorded Investment	56	91	146
Unpaid Principal Balance	56	92	146
Average Recorded Investment	64	102	160
Interest Income Recognized	4	7	11
Related Allowance	0	0	0
With Allowance Recorded [Member]
Impaired loans by loan portfolio
Recorded Investment	11,160	15,428	27,552
Unpaid Principal Balance	12,389	16,409	28,694
Average Recorded Investment	11,552	15,800	28,395
Interest Income Recognized	443	577	936
With Allowance Recorded [Member] \| Commercial and Industrial [Member]
Impaired loans by loan portfolio
Recorded Investment	370	376	10,402
Unpaid Principal Balance	370	376	10,440
Average Recorded Investment	385	391	10,760
Interest Income Recognized	19	19	325
With Allowance Recorded [Member] \| Commercial Real Estate [Member]
Impaired loans by loan portfolio
Recorded Investment	1,287	3,393	5,185
Unpaid Principal Balance	1,287	3,399	5,533
Average Recorded Investment	1,311	3,447	5,491
Interest Income Recognized	74	198	200
With Allowance Recorded [Member] \| Small Business [Member]
Impaired loans by loan portfolio
Recorded Investment	183	147	377
Unpaid Principal Balance	223	153	392
Average Recorded Investment	225	238	408
Interest Income Recognized	13	14	21
With Allowance Recorded [Member] \| Residential Real Estate [Member]
Impaired loans by loan portfolio
Recorded Investment	8,188	9,420	9,959
Unpaid Principal Balance	9,217	10,154	10,530
Average Recorded Investment	8,459	9,575	10,065
Interest Income Recognized	289	284	332
With Allowance Recorded [Member] \| Home Equity [Member]
Impaired loans by loan portfolio
Recorded Investment	991	1,876	1,378
Unpaid Principal Balance	1,149	2,110	1,547
Average Recorded Investment	1,018	1,916	1,403
Interest Income Recognized	43	55	50
With Allowance Recorded [Member] \| Consumer Portfolio Segment [Member]
Impaired loans by loan portfolio
Recorded Investment	141	216	251
Unpaid Principal Balance	143	217	252
Average Recorded Investment	154	233	268
Interest Income Recognized	$ 5	$ 7	$ 8

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-Section 50
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