Fair Value (Additional Information) (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan held for sale, at fair value	$ 6,856,000		$ 15,273,000
Contractual principal balance of Loan held for sale	6,697,000		14,983,000
Difference in amount of loan held for sale	159,000		290,000
Impaired loans, carrying amount	3,214,000		1,575,000
Valuation allowance for loans losses	644,000		355,000
Cost of real estate sales	0	$ 0	75,000
Other real estate, carrying value	0		0
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities	726,352,000		709,786,000
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities	6,800,000		7,648,000
Obligations of State and Political Subdivisions
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total gains/loss included in earnings attributable to other changes in fair value	17,000	121,000
Obligations of State and Political Subdivisions \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities	257,343,000		247,519,000
Total gains/loss included in earnings attributable to other changes in fair value	17,000	121,000
Obligations of State and Political Subdivisions \| Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities	6,447,000		7,295,000
Equity Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total gains/loss included in earnings attributable to interest income	0	0
Equity Securities \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities	353,000		353,000
Total gains/loss included in earnings attributable to other changes in fair value	0	0
Equity Securities \| Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities	353,000		353,000
Commercial Real Estate Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Impaired loans, carrying amount	1,985,000		663,000
Valuation allowance for loans losses	533,000		255,000
Increase (decrease) to provision for loan losses	$ 278,000	$ 5,000	$ 115,000

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Amount of other addition (reduction) in allowance reserve for credit loss.

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Reflects for the period the total of the carrying amount of the commercial, industrial and residential land and buildings sold plus certain overhead and other costs incurred to place the real estate in saleable condition, capitalized interest costs in the properties sold, and inventory impairment losses recognized. This element would most likely be used by an entity whose principal activities involve real estate or which has significant real estate operations.

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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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Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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For loans held as assets for which the fair value option has been elected, this item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of those loans that are 90 days or more past due, in nonaccrual status, or both.

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Amount of allowance for credit losses related to recorded investment.

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Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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Amount, after allowance for bad debt, of mortgage loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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Amount, before accumulated depreciation, of real estate investments for entities with a substantial portion of business acquiring and holding investment real estate.

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