Loans and Allowance for Loan Losses - Purchased Credit-Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	$ 3,350	$ 4,977
Carrying value	2,920	3,681
Increase of specific allowance for PCI loan losses		4	$ 3
Decrease in allowance for loan losses for PCI loans	6	2	238
Accretable Yield [Roll Forward]
Balance at beginning of period	2,618	4,027	3,649
Additions	0	0	0
Removals	(778)	(914)	(273)
Accretion	(364)	(495)	(613)
Reclassifications from nonaccretable difference	0	0	1,264
Balance at end of period	1,476	2,618	$ 4,027
Commercial loans \| Commercial and industrial
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	45	237
Carrying value	40	175
Commercial real estate loans \| Commercial real estate, owner-occupied
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	1,344	2,573
Carrying value	1,072	1,711
Commercial real estate loans \| Commercial real estate, investor
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	1,713	1,756
Carrying value	1,706	1,726
Commercial real estate loans \| Construction
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	0	187
Carrying value	0	1
Residential loans \| Home equity
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	248	224
Carrying value	$ 102	$ 68

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Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

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- Definition

Amount of accretion recognized for the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities, with evidence of deterioration of credit quality.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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Amount of additions to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

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Amount of reduction, resulting from a sale or transfer of a loan, in the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of reduction in the reserve for loans impairments as a result of current information and events which result in it being probable that estimated cash flows will be significantly higher than previously expected or because actual cash flows are significantly greater than cash flows previously expected for loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

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The undiscounted sum of all amounts, including amounts deemed principal, interest, fees, penalties, and other under the loan, owed to the investor at the reporting date, whether or not currently due and whether or not any such amounts have been written or charged off by the investor. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

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-Publisher FASB
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Amount of expense related to loan loss not accounted for as debt securities, with evidence of deterioration of credit quality.

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