EMPLOYEE BENEFITS (Change in Fair Value of Pension Plan Assets) (Details) - Pension Benefits - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 128,430	$ 106,600
Fair value of plan assets at end of year	157,644	128,430
U.S. property separate account fund
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	14,330
Fair value of plan assets at end of year	15,502	14,330
U.S. property separate account fund \| Level 3
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	14,330	11,252
Unrealized gains	1,172	1,078
Purchases		2,000
Fair value of plan assets at end of year	$ 15,502	$ 14,330

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(iv)(02)(A)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from purchases, sales and settlements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(iv)(02)(B)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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