Mergers and acquisitions - Farmers National Bank Narrative (Details) - Farmers National Bank of Scottsville $ / shares in Units, $ in Thousands	Sep. 17, 2019 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) branch
Business Acquisition [Line Items]
Number of branches | branch		5
Assets assumed in acquisition		$ 251,216
Loans assumed in acquisition		174,850
Deposits assumed in acquisition		$ 201,909
Business acquisition, shares issued (in shares) | shares	954,827
Cash purchase price	$ 15,000
Business acquisition, share price | $ / shares	$ 38.26
Business combination, consideration, value	$ 51,900