Investment Securities (Details Textual)	3 Months Ended	12 Months Ended
Mar. 31, 2018 USD ($) Security Investment	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) Security
Investments Debt And Equity Securities [Abstract]
Carrying value of investment securities for pledge	$ 63,800,000		$ 105,000,000
Investment securities with fair value less than amortized cost \| Security	122		83
OTTI loss recognized through impairment assessment process	$ 0	$ 0
Non-accrual investment securities	$ 1,100,000		$ 895,000
Trust preferred securities in nonaccrual status \| Investment	2
Estimated length of interest payment delays	10 years

Interest payment delay period.

No definition available.

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- Definition

Non accrual investment securities.

+ References

No definition available.

+ Details

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- Definition

Number of investment securities having fair value less than related amortized cost.

+ References

No definition available.

+ Details

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- Definition

Trust preferred securities in nonaccrual status.

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 8B
-URI http://asc.fasb.org/extlink&oid=82897076&loc=SL6284393-111563

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- Definition

Sum of the carrying amounts as of the date of the latest financial statement presented of securities which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=64858031&loc=SL6224234-111729

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