Loans and Allowance for Loan Losses - Allowance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Changes in the allowance for loan losses
Balance at beginning of period	$ 11,775	$ 10,939
Charge-offs	(1,756)	0
Recoveries	4	3
Provision (recovery)	1,138	300
Balance at end of period	11,161	11,242
Individually evaluated for impairment	532	1,123
Collectively evaluated for impairment	10,629	10,119
Commercial and Non-Residential Real Estate
Changes in the allowance for loan losses
Balance at beginning of period	10,098	8,605
Charge-offs	(1,756)	0
Recoveries	0	0
Provision (recovery)	1,255	259
Balance at end of period	9,597	8,864
Individually evaluated for impairment	532	1,123
Collectively evaluated for impairment	9,065	7,741
Residential Real Estate
Changes in the allowance for loan losses
Balance at beginning of period	1,272	1,405
Charge-offs	0	0
Recoveries	0	1
Provision (recovery)	0	11
Balance at end of period	1,272	1,417
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,272	1,417
Home Equity
Changes in the allowance for loan losses
Balance at beginning of period	327	684
Charge-offs	0	0
Recoveries	2	1
Provision (recovery)	(93)	19
Balance at end of period	236	704
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	236	704
Consumer
Changes in the allowance for loan losses
Balance at beginning of period	78	245
Charge-offs	0	0
Recoveries	2	1
Provision (recovery)	(24)	11
Balance at end of period	56	257
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	$ 56	$ 257