Loans and Allowance for Loan Losses - Loans outstanding by portfolio segment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Loans and Allowance for Loan Losses
Total loans	$ 1,758,277	$ 1,721,279
Deferred loan fees and costs	994,000	1,000
Commercial
Loans and Allowance for Loan Losses
Total loans	1,050,230	1,000,225
Consumer
Loans and Allowance for Loan Losses
Total loans	708,047	721,054
Commercial and industrial | Commercial
Loans and Allowance for Loan Losses
Total loans	502,637	479,144
Real estate construction | Commercial
Loans and Allowance for Loan Losses
Total loans	25,487	26,378
Residential | Consumer | Real estate first mortgage
Loans and Allowance for Loan Losses
Total loans	457,895	457,155
Residential | Consumer | Real estate junior lien
Loans and Allowance for Loan Losses
Total loans	170,538	177,373
Commercial real estate | Commercial
Loans and Allowance for Loan Losses
Total loans	522,106	494,703
Other revolving and installment | Consumer
Loans and Allowance for Loan Losses
Total loans	$ 79,614	$ 86,526