Allowance for Loan Losses and Reserve for Unfunded Loan Commitments - Activity in the Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 22,965	$ 17,376	$ 23,105	$ 16,395
Charge-offs	(184)	(219)	(840)	(744)
Recoveries	20	577	36	583
Net (charge-offs) recoveries	(164)	358	(804)	(161)
Provision for (credit to) loan losses charged to expense		2,500	500	4,000
Balance, end of period	22,801	20,234	22,801	20,234
SBA loans held for investment
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	1,654	1,005	1,301	1,079
Charge-offs	(164)		(446)	(25)
Recoveries	19	75	34	80
Net (charge-offs) recoveries	(145)	75	(412)	55
Provision for (credit to) loan losses charged to expense	177	(76)	797	(130)
Balance, end of period	1,686	1,004	1,686	1,004
Commercial loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	14,727	10,129	14,992	9,722
Charge-offs	(20)	(219)	(393)	(519)
Recoveries	1	502	2	503
Net (charge-offs) recoveries	(19)	283	(391)	(16)
Provision for (credit to) loan losses charged to expense	303	1,924	410	2,630
Balance, end of period	15,011	12,336	15,011	12,336
Residential mortgage loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	5,009	4,763	5,318	4,254
Charge-offs				(200)
Net (charge-offs) recoveries				(200)
Provision for (credit to) loan losses charged to expense	(405)	676	(714)	1,385
Balance, end of period	4,604	5,439	4,604	5,439
Consumer loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	549	671	681	625
Charge-offs			(1)
Net (charge-offs) recoveries			(1)
Provision for (credit to) loan losses charged to expense	52	(60)	(79)	(14)
Balance, end of period	601	611	601	611
Residential construction loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	1,026	808	813	715
Provision for (credit to) loan losses charged to expense	(127)	36	86	129
Balance, end of period	$ 899	$ 844	$ 899	$ 844

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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- Definition

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 loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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- Definition

Amount, after recoveries, of loans and leases that have been written-off.

+ References

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- Definition

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.

+ References

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Amount of expense related to estimated loss from loan and lease transactions.

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