Securities - Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized cost and fair values of securities
Due in one year or less, amortized cost	$ 89,175
Due in one year or less, fair value	89,175
Total Fair value	103,921	$ 93,383
Total Amortized Cost	103,587	92,876
Equity mutual fund [Member]
Amortized cost and fair values of securities
Total Fair value	0	499
Total Amortized Cost		500
Mortgage - backed securities - residential [Member]
Amortized cost and fair values of securities
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost	10,593
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	10,925
Total Fair value	10,925	12,472
Total Amortized Cost	10,593	11,969
Collateralized mortgage obligations - residential [Member]
Amortized cost and fair values of securities
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost	3,819
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	3,821
Total Fair value	3,821	4,486
Total Amortized Cost	$ 3,819	4,481
SBA-guaranteed loan participation certificates [Member]
Amortized cost and fair values of securities
Total Fair value		10
Total Amortized Cost		$ 10

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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- References

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27198-111563

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), without single maturity date and not allocated over maturity grouping.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
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