Loans, net and allowance for loan losses - Allocation of Allowance for Loan Losses and Related Loans by Major Classification of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Allowance for loan losses:
Ending balance	$ 26,783	$ 27,344	$ 25,686	$ 22,677
Ending balance: individually evaluated for impairment	869	1,202
Ending balance: collectively evaluated for impairment	25,914	26,142
Loans receivable:
Ending balance	2,179,534	2,177,982
Ending balance: individually evaluated for impairment	8,278	9,906
Ending balance: collectively evaluated for impairment	2,171,256	2,168,076
Commercial
Allowance for loan losses:
Ending balance	8,215	8,734	7,969	6,888
Ending balance: individually evaluated for impairment	697	947
Ending balance: collectively evaluated for impairment	7,518	7,787
Loans receivable:
Ending balance	677,090	679,286
Ending balance: individually evaluated for impairment	2,651	4,297
Ending balance: collectively evaluated for impairment	674,439	674,989
Real estate Commercial
Allowance for loan losses:
Ending balance	14,703	14,559	13,007	11,496
Ending balance: individually evaluated for impairment	108	180
Ending balance: collectively evaluated for impairment	14,595	14,379
Loans receivable:
Ending balance	1,150,567	1,137,990
Ending balance: individually evaluated for impairment	3,990	3,952
Ending balance: collectively evaluated for impairment	1,146,577	1,134,038
Real estate Residential
Allowance for loan losses:
Ending balance	2,994	3,129	3,624	3,226
Ending balance: individually evaluated for impairment	64	75
Ending balance: collectively evaluated for impairment	2,930	3,054
Loans receivable:
Ending balance	273,226	277,414
Ending balance: individually evaluated for impairment	1,543	1,546
Ending balance: collectively evaluated for impairment	271,683	275,868
Consumer
Allowance for loan losses:
Ending balance	871	922	$ 1,086	$ 1,067
Ending balance: collectively evaluated for impairment	871	922
Loans receivable:
Ending balance	78,651	83,292
Ending balance: individually evaluated for impairment	94	111
Ending balance: collectively evaluated for impairment	$ 78,557	$ 83,181

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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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.

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