PENSION AND SUPPLEMENTAL EXECUTIVE RETIREMENT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Plan
Components of net periodic benefit cost
Interest cost	$ 232	$ 343	$ 694	$ 1,030
Expected return on plan assets	(264)	(438)	(792)	(1,316)
Amortization of net actuarial loss	298	353	894	1,061
Net periodic cost	266	258	796	775
SERPs
Components of net periodic benefit cost
Interest cost	107	117	322	350
Amortization of net actuarial loss	26	13	77	38
Amortization of net transition obligation	4	4	13	12
Amortization of prior service cost	5	4	13	14
Settlement	0	0	138	0
Net periodic cost	$ 142	$ 138	$ 563	$ 414

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.

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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

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- Definition

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

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- Definition

Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement.

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- Definition

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

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