STOCK-BASED COMPENSATION PLANS - Additional information (Details) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,006
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	575
Proceeds from Stock Options Exercised	$ 1.7	$ 0.8
Unrecognized compensation expense related to stock options	$ 4.3
Weighted-average period of unrecognized compensation expense related to stock options	2 years 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 9.6	4.4
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	$ 1.3	$ 0.1
2017 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Stock options remain reserved for issuance	3,600
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	670
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	251
2017 Stock Option Plan \| Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Shares Vesting period	4 years
2017 Stock Option Plan \| Management [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Shares Vesting period	3 years
2017 Stock Option Plan \| Minimum \| Restricted Stock [Member] \| Share-based Payment Arrangement, Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Shares Vesting period	2 years
2017 Stock Option Plan \| Maximum \| Restricted Stock [Member] \| Share-based Payment Arrangement, Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Shares Vesting period	4 years
2005 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	299
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	299

Aggregate number of common shares reserved for future issuance.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Number of options outstanding, including both vested and non-vested options.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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