PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Service cost	$ 468	$ 1,887	$ 936	$ 3,774
Interest cost	2,416	3,114	4,832	6,228
Expected return on plan assets	(3,612)	(3,655)	(7,224)	(7,310)
Amortization of prior service credit	0	0	0	0
Recognized actuarial loss (gain)	123	2,166	246	4,332
Net periodic benefit (income) cost	(605)	3,512	(1,210)	7,024
Pension Benefits \| Cost of Sales
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Net periodic benefit (income) cost	300	2,000	600	4,000
Pension Benefits \| Selling, General and Administrative Expenses
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Net periodic benefit (income) cost	300	1,500	600	3,000
Other Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Service cost	0	4	0	8
Interest cost	49	80	98	160
Expected return on plan assets	0	0	0	0
Amortization of prior service credit	(280)	(72)	(560)	(144)
Recognized actuarial loss (gain)	(62)	92	(124)	184
Net periodic benefit (income) cost	$ (293)	$ 104	(586)	$ 208
Union Pension Plan
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Expected contributions in current fiscal year			8,000
Nonunion Pension Plan
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Expected contributions in current fiscal year			$ 2,000

The amount of gains or losses recognized in net periodic benefit cost.

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The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation.

+ 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 (h)(1)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Prior Service Cost
-URI http://asc.fasb.org/extlink&oid=49177896

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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.

+ References

No definition available.

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Amount of the employer's best estimate of contributions expected to be paid to the plan in the current fiscal period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2709-114920

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- Definition

An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Expected Return on Plan Assets
-URI http://asc.fasb.org/extlink&oid=6512171

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- Definition

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

+ 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 (h)(2)
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The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

+ 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 (h)
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- Definition

The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Service Cost (Component of Net Periodic Pension Cost)
-URI http://asc.fasb.org/extlink&oid=6525008

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