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TAX, CIVIL AND LABOR CLAIMS AND CONTINGENT ASSETS - Changes in Provisions (Details) - BRL (R$) R$ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016
Changes in the tax, labor and civil provisions : |  |
Balance at the beginning of the year | R$ 2,239,226 |
Balance at the end of the year | 827,883 | R$ 2,239,226
Tax, labor and civil provisions |  |
Changes in the tax, labor and civil provisions : |  |
Balance at the beginning of the year | 2,239,226 | 1,904,730
Additions | 527,543 | 313,246
Monetary correction | (419,567) | 178,661
Reversal of accrued amounts | (1,517,787) | (144,025)
Foreign exchange effect on provisions in foreign currency | (201) | (3,235)
Effect of selling of subsidiary |  | (10,151)
Loss of control by joint venture creation | (1,331) |
Balance at the end of the year | R$ 827,883 | R$ 2,239,226

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