Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	$ 5,610	$ 5,610	$ 19,197
Loans with a specific valuation allowance, Unpaid principal balance	5,612	5,612	19,491
Specific valuation allowance	107	107	3,223
Loans with a specific valuation allowance, Average balance	5,624	11,626	19,519
Loans without a specific valuation allowance, Recorded balance	103,283	103,283	89,591
Loans without a specific valuation allowance, Unpaid principal balance	119,582	119,582	107,486
Loans without a specific valuation allowance, Average balance	99,813	94,391	106,747
Recorded balance	108,893	108,893	108,788
Unpaid principal balance	125,194	125,194	126,977
Average balance	105,437	106,017	126,266
Residential Real Estate | Residential Real Estate
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	0	0	1,957
Loans with a specific valuation allowance, Unpaid principal balance	0	0	2,220
Specific valuation allowance	0	0	83
Loans with a specific valuation allowance, Average balance	22	511	2,686
Loans without a specific valuation allowance, Recorded balance	9,519	9,519	10,728
Loans without a specific valuation allowance, Unpaid principal balance	10,993	10,993	11,989
Loans without a specific valuation allowance, Average balance	10,129	10,397	10,269
Recorded balance	9,519	9,519	12,685
Unpaid principal balance	10,993	10,993	14,209
Average balance	10,151	10,908	12,955
Commercial | Commercial Real Estate
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	5,541	5,541	9,345
Loans with a specific valuation allowance, Unpaid principal balance	5,541	5,541	9,345
Specific valuation allowance	61	61	568
Loans with a specific valuation allowance, Average balance	5,507	6,591	8,498
Loans without a specific valuation allowance, Recorded balance	66,210	66,210	59,492
Loans without a specific valuation allowance, Unpaid principal balance	76,936	76,936	71,300
Loans without a specific valuation allowance, Average balance	61,837	60,567	73,889
Recorded balance	71,751	71,751	68,837
Unpaid principal balance	82,477	82,477	80,645
Average balance	67,344	67,158	82,387
Commercial | Other Commercial
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	69	69	7,268
Loans with a specific valuation allowance, Unpaid principal balance	71	71	7,268
Specific valuation allowance	46	46	2,313
Loans with a specific valuation allowance, Average balance	84	4,360	7,081
Loans without a specific valuation allowance, Recorded balance	20,223	20,223	13,707
Loans without a specific valuation allowance, Unpaid principal balance	23,356	23,356	17,689
Loans without a specific valuation allowance, Average balance	21,137	17,232	17,376
Recorded balance	20,292	20,292	20,975
Unpaid principal balance	23,427	23,427	24,957
Average balance	21,221	21,592	24,457
Consumer and Other | Home Equity
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	0	0	120
Loans with a specific valuation allowance, Unpaid principal balance	0	0	120
Specific valuation allowance	0	0	39
Loans with a specific valuation allowance, Average balance	0	30	82
Loans without a specific valuation allowance, Recorded balance	4,030	4,030	3,377
Loans without a specific valuation allowance, Unpaid principal balance	4,715	4,715	3,986
Loans without a specific valuation allowance, Average balance	3,626	3,421	3,465
Recorded balance	4,030	4,030	3,497
Unpaid principal balance	4,715	4,715	4,106
Average balance	3,626	3,451	3,547
Consumer and Other | Other Consumer
Summary of the impaired loans by portfolio class of loans
Loans with a specific valuation allowance, Recorded balance	0	0	507
Loans with a specific valuation allowance, Unpaid principal balance	0	0	538
Specific valuation allowance	0	0	220
Loans with a specific valuation allowance, Average balance	11	134	1,172
Loans without a specific valuation allowance, Recorded balance	3,301	3,301	2,287
Loans without a specific valuation allowance, Unpaid principal balance	3,582	3,582	2,522
Loans without a specific valuation allowance, Average balance	3,084	2,774	1,748
Recorded balance	3,301	3,301	2,794
Unpaid principal balance	3,582	3,582	3,060
Average balance	$ 3,095	$ 2,908	$ 2,920