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Fair Value Measurement - Summary of Valuation Technique, Unobservable Inputs and Qualitative Information of Assets and Liabilities Measured at Fair Value on Non-recurring Basis (Details) - Level 3 - Fair Value Measurements, Non-recurring | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016
Impaired Loans |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Valuation Technique | Appraisals | Appraisals
Impact to Valuation from an Increased or Higher Input Value | Decrease | Decrease
Impaired Loans | Minimum |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Appraisal adjustments, sales costs and other discount adjsutments for market conditions | 6.00% | 6.00%
Impaired Loans | Maximum |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Appraisal adjustments, sales costs and other discount adjsutments for market conditions | 10.00% | 10.00%
Asset Held For Sale |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Valuation Technique | List price, contract price | List price, contract price
Appraisal adjustments, sales costs and other discount adjsutments for market conditions | 7.00% | 7.00%
Impact to Valuation from an Increased or Higher Input Value | Decrease | Decrease
Other Real Estate Owned |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Valuation Technique | Appraisals | Appraisals
Impact to Valuation from an Increased or Higher Input Value | Decrease | Decrease
Other Real Estate Owned | Minimum |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Appraisal adjustments, sales costs and other discount adjsutments for market conditions | 7.00% | 7.00%
Other Real Estate Owned | Maximum |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] |  |
Appraisal adjustments, sales costs and other discount adjsutments for market conditions | 20.00% | 20.00%

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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. + Details
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- Definition Description of the changes in significant assumptions used by management to measure fair value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 + Details
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- Definition Description of the inputs and valuation technique(s) used 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 + Details
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