PENSION AND SUPPLEMENTAL EXECUTIVE RETIREMENT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Pension Plan
Components of net periodic benefit cost
Interest cost	$ 231	$ 229
Expected return on plan assets	(259)	(264)
Amortization of net actuarial loss	298	296
Net periodic cost	270	261
SERPs
Components of net periodic benefit cost
Interest cost	97	115
Amortization of net actuarial loss	43	26
Amortization of net transition obligation	5	4
Amortization of prior service cost	5	4
Net periodic cost	$ 150	$ 149

Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan.

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- Definition

Amount of transition asset (obligation) recognized in net periodic benefit (cost) credit of defined benefit plan.

+ References

+ Details

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- Definition

Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan.

+ References

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- Definition

Amount of cost recognized for passage of time related to defined benefit plan.

+ 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)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

+ Details

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- Definition

Amount of net periodic benefit cost (credit) for defined benefit plan.

+ References

+ Details

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- References

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- Definition

Amount of gain (loss) recognized in net periodic benefit (cost) credit from settlement and curtailment.

+ References

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- Details

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- Details

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