STOCK OPTIONS AND OTHER EQUITY AWARDS - Stock Option Activity (Details) - $ / shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of Shares
Outstanding at beginning of year (in shares)	1,593,241
Granted (in shares)	126,250
Exercised (in shares)	(305,697)
Forfeited (in shares)	(9,750)
Expired (in shares)	(7,250)
Outstanding at end of year (in shares)	1,396,794	1,593,241
Exercisable at end of year (in shares)	947,988
Weighted-Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 14.96
Granted (in dollars per share)	18.11
Exercised (in dollars per share)	14.36
Forfeited (in dollars per share)	16.85
Expired (in dollars per share)	14.78
Outstanding at end of year (in dollars per share)	15.36	$ 14.96
Exercisable at end of year (in dollars per share)	14.66
Additional disclosure
Weighted-average fair value of options granted during the year (in dollars per share)	$ 4.48	$ 4.22	$ 5.97

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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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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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