SHARE-BASED COMPENSATION PLANS - Company's stock option activity (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
SHARE-BASED COMPENSATION PLANS
Total intrinsic value of stock options exercised	$ 87	$ 3,822
Net proceeds from stock option exercises	161	4,403
Income tax benefit from the exercise of stock options	23	994
Total fair value of stock options vested	$ 750	$ 793

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Amount of tax benefit for recognition of expense of award 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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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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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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