FAIR VALUES OF FINANCIAL INSTRUMENTS: (Details 2) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.00%
Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	50.00%
State and municipal obligations \| Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 3,680	$ 4,210
Valuation Technique(s)	Discounted cash flow	Discounted cash flow
Unobservable Input(s)	Discount rate	Discount rate
State and municipal obligations \| Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	3.05%	3.05%
State and municipal obligations \| Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	5.50%	5.50%
State And Municipal Obligations
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.00%	0.00%
State And Municipal Obligations \| Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Unobservable Input(s)	Probability of default	Probability of default
Other Real Estate \| Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 1,880	$ 2,531
Valuation Technique(s)	Sales comparison/income approach	Sales comparison/income approach
Unobservable Input(s)	Discount rate for age of appraisal and market conditions	Discount rate for age of appraisal and market conditions
Other Real Estate \| Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	5.00%	5.00%
Other Real Estate \| Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	20.00%	20.00%
Impaired Loans \| Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 3,882	$ 1,387
Valuation Technique(s)	Sales comparison/income approach	Sales comparison/income approach
Unobservable Input(s)	Discount rate for age of appraisal and market conditions	Discount rate for age of appraisal and market conditions
Impaired Loans \| Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	0.00%	0.00%
Impaired Loans \| Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Range of Inputs (percent)	50.00%	50.00%

The description of the unobservable input used to measure the fair value of assets at the end of the period.

No definition available.

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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

+ Details

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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

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

+ 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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