Loans and allowance for credit losses - Individually Assessed Allowance for Credit Losses for Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	$ 125,559	$ 170,389	$ 31,139	$ 28,932
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	15,751	14,748	4,805	5,348
Construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	28,576	58,477	10,194	9,729
Residential real estate | 1-to-4 family mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	19,104	19,220	3,112	3,428
Residential real estate | Residential line of credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	5,903	10,534	752	811
Commercial real estate | Owner occupied
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	12,593	4,849	4,109	3,132
Commercial real estate | Non-owner occupied
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	25,768	44,147	4,621	4,149
Consumer and other
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	10,888	11,240	$ 3,002	$ 1,769
Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	28,158	16,832
Real Estate | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	799	0
Real Estate | Construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	3,580	3,877
Real Estate | Residential real estate | 1-to-4 family mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	338	226
Real Estate | Residential real estate | Residential line of credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	1,400	1,174
Real Estate | Commercial real estate | Owner occupied
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	8,117	3,391
Real Estate | Commercial real estate | Non-owner occupied
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	13,899	8,164
Real Estate | Consumer and other
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	25
Financial Assets and Equipment
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	1,161	1,728
Financial Assets and Equipment | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	1,090	1,728
Financial Assets and Equipment | Construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	0	0
Financial Assets and Equipment | Residential real estate | 1-to-4 family mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	0	0
Financial Assets and Equipment | Residential real estate | Residential line of credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	0	0
Financial Assets and Equipment | Commercial real estate | Owner occupied
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	71	0
Financial Assets and Equipment | Commercial real estate | Non-owner occupied
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	0	0
Financial Assets and Equipment | Consumer and other
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	0
Total
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	29,319	18,560
Individually assessed allowance for credit loss	303	1,687
Total | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	1,889	1,728
Individually assessed allowance for credit loss	0	117
Total | Construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	3,580	3,877
Individually assessed allowance for credit loss	92	0
Total | Residential real estate | 1-to-4 family mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	338	226
Individually assessed allowance for credit loss	0	0
Total | Residential real estate | Residential line of credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	1,400	1,174
Individually assessed allowance for credit loss	10	9
Total | Commercial real estate | Owner occupied
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	8,188	3,391
Individually assessed allowance for credit loss	200	30
Total | Commercial real estate | Non-owner occupied
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	13,899	8,164
Individually assessed allowance for credit loss	0	$ 1,531
Total | Consumer and other
Financing Receivable, Allowance for Credit Loss [Line Items]
Type of Collateral	25
Individually assessed allowance for credit loss	$ 1