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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Stock-based compensation (Details) | 12 Months Ended
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Dec. 31, 2017 USD ($) shares
Restricted Stock |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of shares authorized (shares) | 15,000
Age limit for forfeiture of stock award | 65 years
Restricted Stock | Share-based Compensation Award, Vesting Each Year Commencing with First Anniversary Date of Award |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Award vesting rights percent | 20.00%
Restricted Stock | Share-based Compensation Award, Vesting on Fifth Anniversary Date |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Award vesting rights percent | 100.00%
Incentive Compensation Plan |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of shares authorized (shares) | 10,000
Cash compensation | $ | $ 300,000
Director | Directors' Compensation Plan |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of shares authorized (shares) | 20,000
Award requisite service period | 12 months
Trading days period | 30 days
Deferred Compensation, Share-based Payments |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Maximum annual installments period | 10 years

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- Definition Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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