Related party transactions - Schedule of Loans Analysis to Executive Officers, Certain Management, Bank Directors and Their Affiliates (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Financing Receivable, Related Parties [Roll Forward]
Loans outstanding, beginning balance	$ 30,880
New loans and advances	5,870
Change in related party status	4,167
Repayments	(8,200)
Loans outstanding, ending balance	$ 32,717