Fair Value of Financial Instruments, Fair Values of Financial Instruments, Assets, Quantitative Information (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Level 3 [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Fair value estimate		$ 477
Weighted average prepayment speed		3.94%
Impaired loans [Member] \| Nonrecurring [Member] \| Minimum [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Weighted average discount rate	0.00%	0.00%
Impaired loans [Member] \| Nonrecurring [Member] \| Maximum [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Weighted average discount rate	19.00%	33.00%
Impaired loans [Member] \| Nonrecurring [Member] \| Weighted Average [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Weighted average discount rate	8.20%	14.50%
Impaired loans [Member] \| Nonrecurring [Member] \| Level 3 [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Fair value estimate	$ 8,697	$ 2,793
Impaired loans [Member] \| Nonrecurring [Member] \| Carrying Value [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Fair value estimate	$ 8,697	$ 2,793
Foreclosed real estate [Member] \| Nonrecurring [Member] \| Minimum [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Weighted average discount rate		0.00%
Foreclosed real estate [Member] \| Nonrecurring [Member] \| Maximum [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Weighted average discount rate	36.00%	22.00%
Foreclosed real estate [Member] \| Nonrecurring [Member] \| Weighted Average [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Weighted average discount rate	36.00%	11.50%
Foreclosed real estate [Member] \| Nonrecurring [Member] \| Level 3 [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Fair value estimate	$ 23	$ 178
Foreclosed real estate [Member] \| Nonrecurring [Member] \| Carrying Value [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Fair value estimate	23	178
Market Approach [Member] \| Mortgage Servicing Rights [Member] \| Recurring [Member] \| Level 3 [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Fair value estimate	$ 499
Weighted average prepayment speed	3.97%
Market Approach [Member] \| Interest Rate Lock Commitments [Member] \| Recurring [Member] \| Level 3 [Member]
Quantitative Information about Level 3 Fair Value Measurements [Abstract]
Fair value estimate	$ 184	$ 22
Average pull through rate	90.00%	90.00%

Percentage of average pull through rate for fair value input.

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- References

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ 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 (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ 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 (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Rate at which loans or a loan portfolio are expected to prepay principal balances, used as an input to measure fair value.

+ 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 (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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