EMPLOYEE BENEFIT PLANS - Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Change in fair value of plan assets:
Fair value of plan assets on acquisition date	$ 10,622
Fair value of plan assets at end of year		$ 10,622
Pension Plans
Change in projected benefit obligation:
Projected benefit obligation on acquisition date	8,642
Service cost	0
Interest cost	334
Actuarial gain	662
Benefits paid	(269)
Settlements	(349)
Projected benefit obligation at end of year	9,020	8,642
Accumulated benefit obligation	9,020
Change in fair value of plan assets:
Expected return on plan assets	1,022
Contributions by employer	0
Benefits paid	(269)
Settlements	(349)
Fair value of plan assets at end of year	11,026
Overfunded status	(2,006)
Amounts recognized in consolidated balance sheet assets (liabilities)	2,006
Non-qualified Supplemental Executive Retirement Plan
Change in projected benefit obligation:
Projected benefit obligation on acquisition date	3,670	3,811
Service cost	0	72
Interest cost	116	128
Actuarial gain	16	(50)
Benefits paid	(351)	(291)
Projected benefit obligation at end of year	3,451	3,670
Accumulated benefit obligation	3,451	3,670
Change in fair value of plan assets:
Fair value of plan assets on acquisition date	0	0
Expected return on plan assets	0	0
Contributions by employer	351	291
Benefits paid	(351)	(291)
Fair value of plan assets at end of year	0	0
Overfunded status	3,451	3,670
Amounts recognized in consolidated balance sheet assets (liabilities)	$ (3,451)	$ (3,720)

Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

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Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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Amount of payment, which decreases benefit obligation of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract. Excludes decreases to benefit obligation for remeasurement due to settlement.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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

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Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of payment, which decreases plan assets of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract.

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