Loans and Allowance for Loan Losses - Allowance for loan losses (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Allowance for loan losses
Loans and Leases Receivable, Allowance, Beginning Balance	$ 14,958	$ 10,231	$ 10,231
Charge-offs	(631)	(93)	(410)
Recoveries	94	22	121
Provision		1,066	5,016
Loans and Leases Receivable, Allowance, Ending Balance	14,421	11,226	14,958
Ending Balance: Individually evaluated for impairment	1,371	387	2,100
Ending Balance: Collectively evaluated for impairment	13,050	10,839	12,858
Loans receivables:
Ending Balance: Individually evaluated for impairment	18,911	7,299	20,719
Ending Balance: Collectively evaluated for impairment	1,430,536	1,273,447	1,447,602
Loans receivables	1,452,402	1,284,549	1,471,385
Purchased credit impaired
Loans receivables:
Ending Balance: Individually evaluated for impairment	2,955		3,064
Loans receivables	2,955	3,803	3,064
Commercial \| Real Estate
Allowance for loan losses
Loans and Leases Receivable, Allowance, Beginning Balance	9,291	6,399	6,399
Charge-offs	(451)		(115)
Recoveries	24		9
Provision	214	1,208	2,998
Loans and Leases Receivable, Allowance, Ending Balance	9,078	7,607	9,291
Ending Balance: Individually evaluated for impairment	85		625
Ending Balance: Collectively evaluated for impairment	8,993	7,607	8,666
Loans receivables:
Ending Balance: Individually evaluated for impairment	11,976	1,528	13,379
Ending Balance: Collectively evaluated for impairment	768,911	758,788	773,639
Loans receivables	783,783	763,498	790,025
Commercial \| Real Estate \| Purchased credit impaired
Loans receivables:
Loans receivables	2,896	3,182	3,007
Commercial \| Commercial and Industrial
Allowance for loan losses
Loans and Leases Receivable, Allowance, Beginning Balance	2,546	1,275	1,275
Charge-offs	(117)
Recoveries		19	62
Provision	(116)	(124)	1,209
Loans and Leases Receivable, Allowance, Ending Balance	2,313	1,170	2,546
Ending Balance: Individually evaluated for impairment	1,263	298	1,450
Ending Balance: Collectively evaluated for impairment	1,050	872	1,096
Loans receivables:
Ending Balance: Individually evaluated for impairment	6,466	4,502	7,086
Ending Balance: Collectively evaluated for impairment	270,155	101,668	268,248
Loans receivables	276,621	106,542	275,334
Commercial \| Commercial and Industrial \| Purchased credit impaired
Loans receivables:
Loans receivables		372
Commercial \| Construction
Allowance for loan losses
Loans and Leases Receivable, Allowance, Beginning Balance	1,960	2,067	2,067
Provision	23	(163)	(107)
Loans and Leases Receivable, Allowance, Ending Balance	1,983	1,904	1,960
Ending Balance: Collectively evaluated for impairment	1,983	1,904	1,960
Loans receivables:
Ending Balance: Individually evaluated for impairment		820
Ending Balance: Collectively evaluated for impairment	219,187	220,973	222,319
Loans receivables	219,187	221,793	222,319
Consumer \| Real Estate
Allowance for loan losses
Loans and Leases Receivable, Allowance, Beginning Balance	690	417	417
Charge-offs		(3)	(41)
Recoveries	3	1	2
Provision	(41)	72	312
Loans and Leases Receivable, Allowance, Ending Balance	652	487	690
Ending Balance: Individually evaluated for impairment	23	89	25
Ending Balance: Collectively evaluated for impairment	629	398	665
Loans receivables:
Ending Balance: Individually evaluated for impairment	469	449	254
Ending Balance: Collectively evaluated for impairment	158,689	181,721	167,561
Loans receivables	159,217	182,419	167,872
Consumer \| Real Estate \| Purchased credit impaired
Loans receivables:
Loans receivables	59	249	57
Consumer \| Nonresidential
Allowance for loan losses
Loans and Leases Receivable, Allowance, Beginning Balance	471	73	73
Charge-offs	(63)	(90)	(254)
Recoveries	67	2	48
Provision	(80)	73	604
Loans and Leases Receivable, Allowance, Ending Balance	395	58	471
Ending Balance: Collectively evaluated for impairment	395	58	471
Loans receivables:
Ending Balance: Collectively evaluated for impairment	13,594	10,297	15,835
Loans receivables	$ 13,594	$ 10,297	$ 15,835

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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