Fair Value Measurements - Summary of carrying amounts and estimated fair values of financial instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financial assets:
Securities AFS	$ 419,300	$ 400,144
Level 1
Financial assets:
Cash and cash equivalents	143,969	249,526
Certificates of deposit in other banks	0	0
Securities AFS	0	0
Other investments, including equity securities	4,080	2,650
Loans held for sale	0	0
Loans, net	0	0
BOLI	71,796	66,310
MSR asset	0	0
Financial liabilities:
Deposits	0	0
Long-term borrowings	0	0
Level 2
Financial assets:
Cash and cash equivalents	0	0
Certificates of deposit in other banks	5,390	993
Securities AFS	416,470	391,654
Other investments, including equity securities	13,259	13,189
Loans held for sale	10,710	1,662
Loans, net	0	0
BOLI	0	0
MSR asset	0	0
Financial liabilities:
Deposits	0	0
Long-term borrowings	15,135	34,907
Level 3
Financial assets:
Cash and cash equivalents	0	0
Certificates of deposit in other banks	0	0
Securities AFS	2,830	8,490
Other investments, including equity securities	3,358	2,158
Loans held for sale	0	0
Loans, net	2,244,410	2,139,322
BOLI	0	0
MSR asset	6,960	6,347
Financial liabilities:
Deposits	2,584,662	2,614,995
Long-term borrowings	41,544	41,016
Carrying Amount
Financial assets:
Cash and cash equivalents	143,969	249,526
Certificates of deposit in other banks	5,395	993
Securities AFS	419,300	400,144
Other investments, including equity securities	20,697	17,997
Loans held for sale	10,564	1,639
Loans, net	2,229,311	2,153,028
BOLI	71,796	66,310
MSR asset	4,945	3,749
Financial liabilities:
Deposits	2,584,447	2,614,138
Long-term borrowings	57,495	77,305
Estimated Fair Value
Financial assets:
Cash and cash equivalents	143,969	249,526
Certificates of deposit in other banks	5,390	993
Securities AFS	419,300	400,144
Other investments, including equity securities	20,697	17,997
Loans held for sale	10,710	1,662
Loans, net	2,244,410	2,139,322
BOLI	71,796	66,310
MSR asset	6,960	6,347
Financial liabilities:
Deposits	2,584,662	2,614,995
Long-term borrowings	$ 56,679	$ 75,923