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EMPLOYEE BENEFIT PLANS - Weighted average asset allocation by asset category along with target allocation (Details) - Retirement Income Plan	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	100.00%	100.00%
Target Allocation for 2017	100.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	3.30%	0.70%
Target Allocation for 2017, Minimum	0.00%
Target Allocation for 2017, Maximum	5.00%
Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	25.50%	27.60%
Target Allocation for 2017, Minimum	0.00%
Target Allocation for 2017, Maximum	40.00%
International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	20.80%	19.10%
Target Allocation for 2017, Minimum	0.00%
Target Allocation for 2017, Maximum	40.00%
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	25.30%	25.80%
Target Allocation for 2017, Minimum	15.00%
Target Allocation for 2017, Maximum	50.00%
Investments measured at net asset value
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	25.10%	26.80%
Target Allocation for 2017, Minimum	0.00%
Target Allocation for 2017, Maximum	20.00%

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Target allocation of investments of this type to total plan assets presented on a weighted average basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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-Section 50
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Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920

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-Publisher FASB
-Name Accounting Standards Codification
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Target allocation minimum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ 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)(i)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920

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