Securities - Narrative (Details)	12 Months Ended
Dec. 31, 2017 USD ($) security	Dec. 31, 2016 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Securities pledged to secure public deposits, repurchase agreements and other \| $	$ 166,284,000	$ 202,577,000
FHLB letters of credit used as additional collateral amount \| $	$ 190,700,000	130,700,000
Federal Home Loan Bank stock requirement, percentage of outstanding borrowings	4.25%
Federal Reserve Bank stock, stock requirement, percentage of outstanding capital	3.00%
Federal Reserve Bank stock, stock requirement, percentage subject to call	3.00%
Federal Reserve Bank Stock \| $	$ 3,587,000	3,559,000
Investment in FHLB stock \| $	2,523,000	2,665,000
Other-than-temporary impairment losses recognized \| $	$ 0	$ 0
Federal agencies and GSEs
Schedule of Available-for-sale Securities [Line Items]
Number of available for sale securities in unrealized loss positions	24
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Number of available for sale securities in unrealized loss positions	53
Number of available for sale securities in unrealized loss positions for 12 months or more	16
Collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Number of available for sale securities in unrealized loss positions	1
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Number of available for sale securities in unrealized loss positions	50
Corporate
Schedule of Available-for-sale Securities [Line Items]
Number of available for sale securities in unrealized loss positions	2

This line item represents federal home loan bank letters of credit which were used as additional collateral amount.

No definition available.

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- Definition

Represents the percentage of par value of restricted stock out of outstanding borrowings required by Federal Home Loan Bank.

+ References

No definition available.

+ Details

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- Definition

Represents the percentage of par value of restricted stock out of outstanding capital required by Federal Reserve Bank.

+ References

No definition available.

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- Definition

Percentage of Par Value of Federal Reserve Banks Restricted Stock Outstanding Capital Subject to Call

+ References

No definition available.

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- Definition

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

+ References

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=84173941&loc=d3e5086-111524

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- Definition

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=82897076&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.

+ References

No definition available.

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- Definition

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 325
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=75031641&loc=d3e63345-112809

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- Definition

Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

+ References

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- Definition

The amount by which the fair value of an investment 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 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e25351-111560

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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.

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No definition available.

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