EMPLOYEE BENEFIT PLANS - Estimated Future Benefit Payments (Details) - Qualified Pension Plan $ in Thousands	Dec. 31, 2017 USD ($)
Qualified Plan
Estimated future benefit payments under defined benefit pension plan
2018	$ 19,479
2019	20,719
2020	21,062
2021	21,351
2022	23,537
2023 - 2027	116,400
Nonqualified Plan
Estimated future benefit payments under defined benefit pension plan
2018	3,542
2019	7,242
2020	6,087
2021	5,709
2022	6,267
2023 - 2027	$ 23,324

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- Definition

Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

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

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- Definition

Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

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