STOCK-BASED COMPENSATION - Restricted stock activity (Details) - $ / shares	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019
Performance-based restricted stock
Number of Shares
Outstanding, beginning of period	18,000	24,000
Forfeited	(750)
Outstanding, end of period	17,250	24,000
Weighted Average Grant Date Fair Value
Outstanding, beginning of period	$ 34.46	$ 34.46
Forfeited	31.79
Outstanding, end of period	$ 34.57	$ 34.46
Non-performance based restricted stock
Number of Shares
Outstanding, beginning of period	161,443	181,773
Granted	40,594	35,687
Vested	(14,550)	(3,100)
Forfeited	(8,656)	(3,207)
Outstanding, end of period	178,831	211,153
Weighted Average Grant Date Fair Value
Outstanding, beginning of period	$ 28.20	$ 27.05
Granted	28.55	32.26
Vested	31.71	29.69
Forfeited	27.22	29.98
Outstanding, end of period	$ 28.04	$ 27.85

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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- Definition

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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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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-Publisher FASB
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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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-Publisher FASB
-Name Accounting Standards Codification
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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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