EMPLOYEE BENEFITS - Post-employment health care benefit plan - Change in plan assets (Details) - Post-employment health care benefit - Fair value of plan assets - BRL (R$) R$ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
EMPLOYEE BENEFITS
Fair value of the plan assets at the beginning of the year	R$ 0	R$ 0
Contributions from sponsors	12,572	12,463	R$ 14,733
Contributions from participants	1,556	2,212	2,206
Payment of benefits	(14,128)	(14,675)	(16,939)
Fair value of plan assets at the end of the year	R$ 0	R$ 0	R$ 0

The decrease (increase) in net defined benefit liability (asset) resulting from contributions to a defined benefit plan by the employer. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]]

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- Definition

The decrease (increase) in the net defined benefit liability (asset) resulting from contributions to a defined benefit plan by plan participants. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]]

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The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The decrease (increase) in the net defined benefit liability (asset) resulting from payments from the plan. [Refer: Net defined benefit liability (asset)]

+ References

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