Loans, net and allowance for loan losses - Major Classifications of Loans Outstanding (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable
Loans	$ 2,179,534	$ 2,177,982
Commercial
Accounts, Notes, Loans and Financing Receivable
Loans	677,090	679,286
Real estate Commercial
Accounts, Notes, Loans and Financing Receivable
Loans	1,150,567	1,137,990
Real estate Residential
Accounts, Notes, Loans and Financing Receivable
Loans	273,226	277,414
Consumer
Accounts, Notes, Loans and Financing Receivable
Loans	$ 78,651	$ 83,292

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121593590&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5074-111524

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant