Related party transactions - Schedule of Loans Analysis to Executive Officers, Certain Management, Bank Directors and Their Affiliates (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Financing Receivable, Related Parties [Roll Forward]
Loans outstanding, beginning balance	$ 30,880
New loans and advances	5,619
Change in related party status	248
Repayments	(5,151)
Loans outstanding, ending balance	$ 31,596