EMPLOYEE BENEFIT PLANS - Weighted Average Assumptions (Details) - Qualified Pension Plan	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Qualified Plan
Weighted-average assumptions used to determine benefit obligations
Discount rate (as a percent)	4.21%	3.55%
Rate of compensation increase prior to age 40 (as a percent)	4.75%	4.75%
Rate of compensation increase age 40 and above (as a percent)	3.75%	3.75%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)	3.55%	4.04%	4.29%
Rate of compensation increase prior to age 40 (as a percent)	4.75%	4.75%	4.75%
Rate of compensation increase age 40 and above (as a percent)	3.75%	3.75%	3.75%
Expected long-term return on plan assets (as a percent)	7.00%	7.00%	7.25%
Nonqualified Plan
Weighted-average assumptions used to determine benefit obligations
Discount rate (as a percent)	3.93%	3.26%
Rate of compensation increase prior to age 40 (as a percent)	4.75%	4.75%
Rate of compensation increase age 40 and above (as a percent)	3.75%	3.75%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)	3.25%	3.60%	3.63%
Rate of compensation increase prior to age 40 (as a percent)	4.75%	4.75%	4.75%
Rate of compensation increase age 40 and above (as a percent)	3.75%	3.75%	3.75%

Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase, Age 40 and Above

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- Definition

Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Prior to Age 40

+ References

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- Definition

Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase, Age 40 And Above

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- Definition

Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Prior to Age 40

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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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