STOCK BASED COMPENSATION PLANS - (Details) - shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
ISOP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance	1,012,500
Purchase price as percent of trading value	100.00%
Term of plan	10 years
ISOP \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
ISOP \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	7 years
2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance	420,000
Term of plan	10 years
Stock award granted to one individual, maximum	30,000
2019 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance	500,000
Term of plan	10 years
Shares available for grant under this plan	330,188
Long Term Incentive Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of plan	3 years
Performance stock units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under this plan	0	0
Performance stock units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under this plan	37,562	26,956
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years

Share-based Compensation Arrangement By Share-based Payment Award Term Of Plan.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

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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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- Definition

The highest quantity of shares an employee can purchase under the plan per period.

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Number of shares authorized for issuance under share-based payment arrangement.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

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