Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	$ 21,539	$ 21,539	$ 34,683
Loans with a specific valuation allowance, Unpaid principal balance	21,812	21,812	36,157
Specific valuation allowance	5,966	5,966	8,124
Loans with a specific valuation allowance, Average balance	22,641	27,899	36,176
Loans without a specific valuation allowance, Recorded balance	113,614	113,614	106,090
Loans without a specific valuation allowance, Unpaid principal balance	136,316	136,316	132,718
Loans without a specific valuation allowance, Average balance	110,336	108,999	116,356
Recorded balance	135,153	135,153	140,773
Unpaid principal balance	158,128	158,128	168,875
Average balance	132,977	136,898	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	3,024	3,024	8,253
Loans with a specific valuation allowance, Unpaid principal balance	3,086	3,086	9,198
Specific valuation allowance	880	880	782
Loans with a specific valuation allowance, Average balance	3,100	5,489	6,393
Loans without a specific valuation allowance, Recorded balance	14,312	14,312	12,514
Loans without a specific valuation allowance, Unpaid principal balance	15,857	15,857	13,969
Loans without a specific valuation allowance, Average balance	14,692	13,859	13,615
Recorded balance	17,336	17,336	20,767
Unpaid principal balance	18,943	18,943	23,167
Average balance	17,792	19,348	20,008
Commercial | Commercial Real Estate
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	10,378	10,378	12,554
Loans with a specific valuation allowance, Unpaid principal balance	10,379	10,379	12,581
Specific valuation allowance	1,375	1,375	1,629
Loans with a specific valuation allowance, Average balance	10,223	10,769	15,827
Loans without a specific valuation allowance, Recorded balance	74,387	74,387	73,291
Loans without a specific valuation allowance, Unpaid principal balance	91,472	91,472	94,028
Loans without a specific valuation allowance, Average balance	70,029	71,278	78,684
Recorded balance	84,765	84,765	85,845
Unpaid principal balance	101,851	101,851	106,609
Average balance	80,252	82,047	94,511
Commercial | Other Commercial
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	7,125	7,125	11,923
Loans with a specific valuation allowance, Unpaid principal balance	7,280	7,280	12,335
Specific valuation allowance	3,120	3,120	5,277
Loans with a specific valuation allowance, Average balance	8,156	10,096	11,768
Loans without a specific valuation allowance, Recorded balance	16,911	16,911	11,951
Loans without a specific valuation allowance, Unpaid principal balance	19,412	19,412	15,539
Loans without a specific valuation allowance, Average balance	17,428	15,637	15,479
Recorded balance	24,036	24,036	23,874
Unpaid principal balance	26,692	26,692	27,874
Average balance	25,584	25,733	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	234	234	102
Loans with a specific valuation allowance, Unpaid principal balance	244	244	109
Specific valuation allowance	196	196	64
Loans with a specific valuation allowance, Average balance	195	237	426
Loans without a specific valuation allowance, Recorded balance	5,642	5,642	6,391
Loans without a specific valuation allowance, Unpaid principal balance	7,125	7,125	7,153
Loans without a specific valuation allowance, Average balance	5,964	6,105	6,350
Recorded balance	5,876	5,876	6,493
Unpaid principal balance	7,369	7,369	7,262
Average balance	6,159	6,342	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	778	778	1,851
Loans with a specific valuation allowance, Unpaid principal balance	823	823	1,934
Specific valuation allowance	395	395	372
Loans with a specific valuation allowance, Average balance	967	1,308	1,762
Loans without a specific valuation allowance, Recorded balance	2,362	2,362	1,943
Loans without a specific valuation allowance, Unpaid principal balance	2,450	2,450	2,029
Loans without a specific valuation allowance, Average balance	2,223	2,120	2,228
Recorded balance	3,140	3,140	3,794
Unpaid principal balance	3,273	3,273	3,963
Average balance	$ 3,190	$ 3,428	$ 3,990