Loans - Average Recorded Investments in Impaired Loans and Related Amount of Interest Recognized (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Impaired [Line Items]
Loans, Average recorded investment	$ 3,810	$ 665	$ 3,203	$ 1,695
Loans, Interest income recognized on impaired loans	55	29	78	67
SBA loans held for investment
Financing Receivable, Impaired [Line Items]
Loans, Average recorded investment	1,275	369	1,003	785
Loans, Interest income recognized on impaired loans	0	29	(2)	45
SBA 504 loans
Financing Receivable, Impaired [Line Items]
Loans, Average recorded investment			0	110
Loans, Interest income recognized on impaired loans			0	0
Commercial loans \| Other
Financing Receivable, Impaired [Line Items]
Loans, Average recorded investment	11	25	10	25
Loans, Interest income recognized on impaired loans	0	0	0	0
Commercial loans \| Commercial real estate
Financing Receivable, Impaired [Line Items]
Loans, Average recorded investment	2,524	271	2,190	775
Loans, Interest income recognized on impaired loans	55	0	80	22
Small Business Administration
Financing Receivable, Impaired [Line Items]
Impaired financing receivable average recorded investment, guaranteed by Small Business Administration	$ 120	$ 446	$ 82	$ 249

Impaired Financing Receivable Average Recorded Investment, Guaranteed by the Small Business Administration

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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