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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, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	100.00%	100.00%
Target Allocation for 2016	100.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	0.70%	1.00%
Target Allocation for 2016, Minimum	0.00%
Target Allocation for 2016, Maximum	5.00%
Debt Securities - Core Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	25.80%	24.30%
Target Allocation for 2016, Minimum	15.00%
Target Allocation for 2016, Maximum	50.00%
Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	38.50%	37.00%
Target Allocation for 2016, Minimum	0.00%
Target Allocation for 2016, Maximum	40.00%
International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	23.20%	22.80%
Target Allocation for 2016, Minimum	0.00%
Target Allocation for 2016, Maximum	30.00%
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	7.20%	10.50%
Target Allocation for 2016, Minimum	0.00%
Target Allocation for 2016, Maximum	20.00%
Real Return
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	0.00%	1.60%
Target Allocation for 2016, Minimum	0.00%
Target Allocation for 2016, Maximum	20.00%
Alternative/Opportunistic/Special
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets	4.60%	2.80%
Target Allocation for 2016, Minimum	0.00%
Target Allocation for 2016, 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=58740216&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=58740216&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=58740216&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=58740216&loc=d3e2446-114920

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