INCENTIVE PLANS (Summary of Activity for Nonvested Performance/Restricted Share Units) (Details) - $ / shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target Number of Shares, Beginning Balance	498,979
Target Number of Shares, Granted	130,715
Target Number of Shares, Vested	(218,725)
Target Number of Shares, Canceled/forfeited	(60,291)
Target Number of Shares, Ending Balance	350,678	498,979
Weighted-average Grant Date Fair Value, Beginning Balance	$ 89.16
Weighted-average Grant Date Fair Value, Granted	117.20	$ 117.49	$ 87.77
Weighted-average Grant Date Fair Value, Vested	74.85
Weighted-average Grant Date Fair Value, Canceled/forfeited	103.56
Weighted-average Grant Date Fair Value, Ending Balance	$ 106.06	$ 89.16
Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target Number of Shares, Beginning Balance	109,302
Target Number of Shares, Granted	52,065
Target Number of Shares, Vested	(11,622)
Target Number of Shares, Canceled/forfeited	(4,366)
Target Number of Shares, Ending Balance	145,379	109,302
Weighted-average Grant Date Fair Value, Beginning Balance	$ 97.43
Weighted-average Grant Date Fair Value, Granted	117.20
Weighted-average Grant Date Fair Value, Vested	100.35
Weighted-average Grant Date Fair Value, Canceled/forfeited	110.73
Weighted-average Grant Date Fair Value, Ending Balance	$ 103.88	$ 97.43

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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- Definition

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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