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EQUITY (Details) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Sep. 19, 2016
Stock-based compensation |  |  |  |
Number of shares reserved to be granted under the plan | 2,000,000 |  |  |
Number of shares available for grant | 723,000 |  |  |
Treasury Stock |  |  |  |
Shares Repurchased | 45,807 | 171,907 | 171,907 |
Aggregate Cost | $ 2,582,000 | $ 12,437,000 | $ 12,983,000 |
Shares repurchased to satisfy tax withholdings and exercise obligations | 42,703 | 141,180 | 32,814 |
Aggregate cost to satisfy tax withholdings and exercise obligations | $ 2,419,000 | $ 10,859,000 | $ 2,348,000 |
Average Repurchase Price (in dollars per share) | $ 56.65 | $ 76.76 | $ 72.50 |
Number of Options |  |  |  |
Exercised (in shares) | (17,000) | (158,021) | (158,021) |
Stock-based compensation, additional disclosures |  |  |  |
Cash proceeds received upon exercise of options |  | $ 72,000 | $ 1,030,000 |
2016 Repurchase Plan |  |  |  |
Treasury Stock |  |  |  |
Authorized amount |  |  |  | $ 50,000,000.0
Shares Repurchased | 3,104 | 30,427 | 201,932 |
Aggregate Cost | $ 162,000 | $ 1,577,000 | $ 10,636,000 |
Average Repurchase Price (in dollars per share) | $ 52.37 | $ 51.82 | $ 52.67 |
Value of shares available for repurchase | $ 37,500,000 |  |  |
Stock options |  |  |  |
Stock-based compensation |  |  |  |
Expiration term | 10 years |  |  |
Vesting period | 4 years |  |  |
Number of Options |  |  |  |
Outstanding at the beginning of the period (in shares) | 42,000 | 200,021 |  |
Granted (in shares) | 0 | 0 |  |
Forfeited (in shares) | (7,500) |  |  |
Expired (in shares) | (2,500) |  |  |
Exercised (in shares) | (17,000) | (158,021) |  |
Outstanding at the end of the period (in shares) | 15,000 | 42,000 | 200,021 |
Vested and expected to vest at the end of the period (in shares) | 15,000 | 42,000 |  |
Exercisable at the end of the period (in shares) | 15,000 | 33,250 |  |
Weighted Avg. Exercise Price |  |  |  |
Outstanding at the beginning of the period (in dollars per share) | $ 48.61 | $ 41.76 |  |
Forfeited (in dollars per share) | 52.97 |  |  |
Expired (in dollars per share) | 52.97 |  |  |
Exercised (in dollars per share) | 45.39 | 39.95 |  |
Outstanding at the end of the period (in dollars per share) | 49.34 | 48.61 | $ 41.76 |
Vested and expected to vest at the end of the period (in dollars per share) | 49.34 | 48.61 |  |
Exercisable at the end of the period (in dollars per share) | $ 49.34 | $ 46.76 |  |
Weighted Average Remaining Contractual Term |  |  |  |
Outstanding | 3 years 2 months 12 days | 4 years 1 month 6 days |  |
Vested and expected to vest | 3 years 2 months 12 days | 4 years 1 month 6 days |  |
Exercisable | 3 years 2 months 12 days | 3 years |  |
Aggregate Intrinsic Value |  |  |  |
Outstanding | $ 170,900 | $ 823,515 |  |
Vested and expected to vest | 170,900 | 962,840 |  |
Exercisable | 170,900 | 823,515 |  |
Stock-based compensation, additional disclosures |  |  |  |
Weighted-average fair value of options granted (in dollars per share) |  |  | $ 13.77 |
Aggregate intrinsic value of options exercised | 229,000 | 5,927,000 | $ 936,000 |
Cash proceeds received upon exercise of options |  | 72,000 | $ 1,030,000 |
Weighted-average assumptions using Black-Scholes option-pricing model for estimating fair value of each option granted |  |  |  |
Risk-free interest rate (as a percent) |  |  | 1.79% |
Expected dividend yield (as a percent) |  |  | 1.28% |
Expected life |  |  | 4 years |
Expected volatility (as a percent) |  |  | 34.01% |
Stock compensation expense |  |  |  |
Stock compensation expense | $ 0 | 100,000 | $ 100,000 |
Restricted Stock |  |  |  |
Stock-based compensation |  |  |  |
Vesting period | 4 years |  |  |
Unamortized stock based compensation |  |  |  |
Unamortized stock based compensation | $ 8,200,000 |  |  |
Weighted-average period for recognition of unamortized stock-based compensation cost | 2 years 4 months 24 days |  |  |
Stock compensation expense |  |  |  |
Stock compensation expense | $ 6,400,000 | $ 6,100,000 | $ 6,600,000 |
Shares |  |  |  |
Unvested at the beginning of the period (in shares) | 200,653 | 214,938 |  |
Granted (in shares) | 108,278 | 111,474 | 95,095 |
Forfeited (in shares) | (18,579) | (31,327) |  |
Vested and issued (in shares) | (86,206) | (94,432) |  |
Unvested at the end of the period (in shares) | 204,146 | 200,653 | 214,938 |
Weighted Avg. Fair Value |  |  |  |
Unvested at the beginning of the period (in dollars per share) | $ 65.21 | $ 68.62 |  |
Granted (in dollars per share) | 54.68 | 59.52 |  |
Forfeited (in dollars per share) | 57.04 | 66.53 |  |
Vested and issued (in dollars per share) | 65.77 | 66.27 |  |
Unvested at the end of the period (in dollars per share) | $ 60.13 | $ 65.21 | $ 68.62 |
Restricted Stock | Management |  |  |  |
Stock compensation expense |  |  |  |
Stock compensation expense |  | $ 200,000 | $ 300,000 |

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- Definition Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur. + References 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 (e) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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