The fair value of available-for-sale securities that serve as collateral for borrowings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5086-111524

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Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

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Number of investment positions in available-for-sale investments that have been in a continuous unrealized loss position for greater than or equal to a year for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

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The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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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.

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Securities - Additional Information (Details)	12 Months Ended
Securities - Additional Information (Details)	Dec. 31, 2017 USD ($) security	Dec. 31, 2016 USD ($)
Investments, Debt and Equity Securities [Abstract]
Securities pledged as collateral \| $	$ 21,800,000	$ 24,600,000
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities, unrealized loss position more than 12 months	1
Other-than-temporarily impairment \| $	$ 0
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities, unrealized loss position more than 12 months	55
Number of securities	101
State and political subdivision
Schedule of Available-for-sale Securities [Line Items]
Number of securities	41
U.S. agency collateralized mortgage obligations: residential
Schedule of Available-for-sale Securities [Line Items]
Number of securities	25
U.S. government sponsored entities and agencies
Schedule of Available-for-sale Securities [Line Items]
Number of securities	12
U.S. agency mortgage-backed securities: residential
Schedule of Available-for-sale Securities [Line Items]
Number of securities	10
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporarily impairment \| $	$ 508,000
Number of securities	8
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Number of securities	5