Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Summary of the impaired loans by portfolio class of loans
Loans with a Specific Valuation Allowance, Recorded Balance	$ 22,128	$ 34,683
Loans with a Specific Valuation Allowance, Unpaid Principal Balance	22,374	36,157
Specific valuation allowance	6,881	8,124
Loans with a Specific Valuation Allowance, Average Balance	26,745	36,176
Loans without a Specific Valuation Allowance, Recorded Balance	108,135	106,090
Loans without a Specific Valuation Allowance, Unpaid Principal Balance	131,059	132,718
Loans without a Specific Valuation Allowance, Average Balance	108,827	116,356
Recorded balance	130,263	140,773
Unpaid principal balance	153,433	168,875
Average balance	135,572	152,532
Residential Real Estate | Residential Real Estate
Summary of the impaired loans by portfolio class of loans
Loans with a Specific Valuation Allowance, Recorded Balance	2,759	8,253
Loans with a Specific Valuation Allowance, Unpaid Principal Balance	2,825	9,198
Specific valuation allowance	856	782
Loans with a Specific Valuation Allowance, Average Balance	4,942	6,393
Loans without a Specific Valuation Allowance, Recorded Balance	8,853	12,514
Loans without a Specific Valuation Allowance, Unpaid Principal Balance	9,925	13,969
Loans without a Specific Valuation Allowance, Average Balance	12,858	13,615
Recorded balance	11,612	20,767
Unpaid principal balance	12,750	23,167
Average balance	17,800	20,008
Commercial | Commercial Real Estate
Summary of the impaired loans by portfolio class of loans
Loans with a Specific Valuation Allowance, Recorded Balance	9,129	12,554
Loans with a Specific Valuation Allowance, Unpaid Principal Balance	9,130	12,581
Specific valuation allowance	922	1,629
Loans with a Specific Valuation Allowance, Average Balance	10,441	15,827
Loans without a Specific Valuation Allowance, Recorded Balance	76,505	73,291
Loans without a Specific Valuation Allowance, Unpaid Principal Balance	94,180	94,028
Loans without a Specific Valuation Allowance, Average Balance	72,323	78,684
Recorded balance	85,634	85,845
Unpaid principal balance	103,310	106,609
Average balance	82,764	94,511
Commercial | Other Commercial
Summary of the impaired loans by portfolio class of loans
Loans with a Specific Valuation Allowance, Recorded Balance	8,814	11,923
Loans with a Specific Valuation Allowance, Unpaid Principal Balance	8,929	12,335
Specific valuation allowance	4,419	5,277
Loans with a Specific Valuation Allowance, Average Balance	9,840	11,768
Loans without a Specific Valuation Allowance, Recorded Balance	15,136	11,951
Loans without a Specific Valuation Allowance, Unpaid Principal Balance	17,724	15,539
Loans without a Specific Valuation Allowance, Average Balance	15,537	15,479
Recorded balance	23,950	23,874
Unpaid principal balance	26,653	27,874
Average balance	25,377	27,247
Consumer and Other | Home Equity
Summary of the impaired loans by portfolio class of loans
Loans with a Specific Valuation Allowance, Recorded Balance	334	102
Loans with a Specific Valuation Allowance, Unpaid Principal Balance	345	109
Specific valuation allowance	296	64
Loans with a Specific Valuation Allowance, Average Balance	257	426
Loans without a Specific Valuation Allowance, Recorded Balance	5,600	6,391
Loans without a Specific Valuation Allowance, Unpaid Principal Balance	7,120	7,153
Loans without a Specific Valuation Allowance, Average Balance	6,004	6,350
Recorded balance	5,934	6,493
Unpaid principal balance	7,465	7,262
Average balance	6,261	6,776
Consumer and Other | Other Consumer
Summary of the impaired loans by portfolio class of loans
Loans with a Specific Valuation Allowance, Recorded Balance	1,092	1,851
Loans with a Specific Valuation Allowance, Unpaid Principal Balance	1,145	1,934
Specific valuation allowance	388	372
Loans with a Specific Valuation Allowance, Average Balance	1,265	1,762
Loans without a Specific Valuation Allowance, Recorded Balance	2,041	1,943
Loans without a Specific Valuation Allowance, Unpaid Principal Balance	2,110	2,029
Loans without a Specific Valuation Allowance, Average Balance	2,105	2,228
Recorded balance	3,133	3,794
Unpaid principal balance	3,255	3,963
Average balance	$ 3,370	$ 3,990