Loans - Aging Analysis of Past Due and Nonaccrual Loans by Class (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	$ 14,430	$ 8,308
Loans receivable, nonaccrual status	6,195	2,994
Loans receivable, current	1,255,845	1,139,556
Loan receivable, current	1,268,874	1,162,366
Total loans	1,270,275	1,147,864
SBA loans held for sale	13,029	22,810
Total loans	1,283,304	1,170,674
30-59 days past due
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	6,544	2,705
60-89 days past due
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	1,145	2,549
90 days and still accruing
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	546	60
SBA loans held for investment
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	1,297	1,185
Loans receivable, nonaccrual status	1,297	632
Loan receivable, current	39,754	42,814
Total loans	41,051	43,999
SBA loans held for investment \| 30-59 days past due
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	240
SBA loans held for investment \| 60-89 days past due
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	313
SBA loans held for investment \| 90 days and still accruing
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
SBA 504 loans
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Loans receivable, nonaccrual status	0	0
Loan receivable, current	29,530	21,871
Total loans	29,530	21,871
SBA 504 loans \| 30-59 days past due
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
SBA 504 loans \| 60-89 days past due
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
SBA 504 loans \| 90 days and still accruing
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Commercial loans
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, nonaccrual status	1,000
Total loans	697,075	628,865
Commercial loans \| Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	51	108
Loans receivable, nonaccrual status	15	25
Loan receivable, current	102,504	82,717
Total loans	102,555	82,825
Commercial loans \| Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	3,431	1,674
Loans receivable, nonaccrual status	1,219	43
Loan receivable, current	513,203	468,022
Total loans	516,634	469,696
Commercial loans \| Commercial real estate construction
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Loans receivable, nonaccrual status	0	0
Loan receivable, current	48,356	54,473
Total loans	48,356	54,473
Commercial loans \| 30-59 days past due \| Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	36	23
Commercial loans \| 30-59 days past due \| Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	2,212	558
Commercial loans \| 30-59 days past due \| Commercial real estate construction
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Commercial loans \| 60-89 days past due \| Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Commercial loans \| 60-89 days past due \| Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	1,073
Commercial loans \| 60-89 days past due \| Commercial real estate construction
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Commercial loans \| 90 days and still accruing \| Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	60
Commercial loans \| 90 days and still accruing \| Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Commercial loans \| 90 days and still accruing \| Commercial real estate construction
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Residential mortgage loans
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	9,266	4,457
Loans receivable, nonaccrual status	3,536	1,669
Loan receivable, current	404,386	360,688
Total loans	413,652	365,145
Residential mortgage loans \| 30-59 days past due
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	4,234	1,830
Residential mortgage loans \| 60-89 days past due
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	950	958
Residential mortgage loans \| 90 days and still accruing
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	546	0
Consumer loans
Financing Receivable, Recorded Investment [Line Items]
Total loans	118,497	109,855
Consumer loans \| Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	3
Loans receivable, nonaccrual status	0	0
Loan receivable, current	58,794	54,035
Total loans	58,794	54,038
Consumer loans \| Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	385	881
Loans receivable, nonaccrual status	128	625
Loan receivable, current	59,318	54,936
Total loans	59,703	55,817
Consumer loans \| 30-59 days past due \| Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	3
Consumer loans \| 30-59 days past due \| Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	62	51
Consumer loans \| 60-89 days past due \| Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Consumer loans \| 60-89 days past due \| Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	195	205
Consumer loans \| 90 days and still accruing \| Other
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Consumer loans \| 90 days and still accruing \| Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, past due	0	0
Small Business Administration
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, nonaccrual status	573
Collateral Pledged \| Small Business Administration
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, nonaccrual status	$ 104	$ 27

Financing receivables that are current.

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