Fair Value (Narrative Disclosures) (Details) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount1	$ 0	$ 0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount1	0	0
Fair value, assets, transfers into level 3	0	0
Fair value, assets, transfers out of level 3	0	0
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount1	0	0
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount1	0	0
Fair value, liabilities, transfers into level 3	0	0
Fair value, liabilities, transfers out of level 3	0	0
Servicing Asset at Fair Value, Amount	1,839,000	1,906,000
Commercial paper	17,400,000	20,300,000
FHLB stock par value equals carrying value	$ 100.00
Minimum
Fair Value Inputs, Assets, Quantitative Information
Quantification of unobservable inputs for level 3 values for impaired loans	15.00%
Maximum
Fair Value Inputs, Assets, Quantitative Information
Quantification of unobservable inputs for level 3 values for impaired loans	21.00%
Weighted average
Fair Value Inputs, Assets, Quantitative Information
Quantification of unobservable inputs for level 3 values for impaired loans	18.00%
Impaired loans
Fair Value Inputs, Assets, Quantitative Information
Assets measured on a non-recurring basis, fair value	$ 15,147,000	13,365,000
Foreclosed properties
Fair Value Inputs, Assets, Quantitative Information
Assets measured on a non-recurring basis, fair value	1,069,000	1,472,000
Fair Value Measurements - Level 3 Inputs \| Impaired loans
Fair Value Inputs, Assets, Quantitative Information
Assets measured on a non-recurring basis, fair value	5,084,000	1,097,000
Fair Value Measurements - Level 3 Inputs \| Foreclosed properties
Fair Value Inputs, Assets, Quantitative Information
Assets measured on a non-recurring basis, fair value	$ 0	$ 0

Fair Value, Assets, Level 1 to Level 2 Transfers, Amount1

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- Definition

Fair Value, Assets, Level 2 to Level 1 Transfers, Amount1

+ References

No definition available.

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- Definition

Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount1

+ References

No definition available.

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- Definition

Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount1

+ References

No definition available.

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- Definition

FHLB Stock Par Value

+ References

No definition available.

+ Details

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- Definition

Quantification of unobservable inputs for Level 3 values for impaired loans

+ References

No definition available.

+ Details

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- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

+ Details

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- Definition

Unsecured short-term debt instrument issued by corporations which are highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3052-108585

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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

Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy.

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- Definition

Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

+ References

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- Definition

Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

+ References

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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

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