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TRADE ACCOUNTS RECEIVABLE - Changes in allowance (Details) - Trade accounts receivable - BRL (R$) R$ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Changes in the allowance |  |  |
Allowance at beginning of period | R$ (199,306) | R$ (185,261) | R$ (98,814)
Provisions for bad debt during the year | (98,476) | (85,661) | (133,868)
Recoveries in the year | 80,134 | 16,880 | 6,167
Write-offs | 73,591 | 37,679 | 41,392
Loss of control by selling of subsidiary |  | 17,594 |
Loss of control by joint venture creation | 1,487 |  |
Assets held for sale | 11,207 |  |
Exchange variation | (276) | (537) | (138)
Allowance at end of period | R$ (131,639) | R$ (199,306) | R$ (185,261)

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- Definition The decrease in an allowance account for credit losses of financial assets resulting from the loss of control in a joint venture. + References No definition available. + Details
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- Definition The decrease in an allowance account for credit losses of financial assets resulting from the loss of control in a subsidiary. + References No definition available. + Details
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- Definition The decrease in allowance for trade receivables through transfer to assets held for sale. + References No definition available. + Details
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- Definition The amount of additional allowance for credit losses of financial assets recognised in profit or loss. [Refer: Allowance account for credit losses of financial assets] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Note Expiry date 2018-01-01 -Name IFRS -Number 7 -IssueDate 2017-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_16&doctype=Standard&book=B -URIDate 2017-03-09 + Details
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- Definition The amount of an allowance account used to record impairments to financial assets due to credit losses. [Refer: Financial assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Note Expiry date 2018-01-01 -Name IFRS -Number 7 -IssueDate 2017-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_16&doctype=Standard&book=B -URIDate 2017-03-09 + Details
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Balance Type: | credit
Period Type: | instant

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- Definition The increase (decrease) in an allowance account for credit losses of financial assets resulting from the net exchange differences arising when the financial statements are translated from the functional currency into a different presentation currency, including the translation of a foreign operation into the presentation currency of the reporting entity. [Refer: Allowance account for credit losses of financial assets] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Note Expiry date 2018-01-01 -Name IFRS -Number 7 -IssueDate 2017-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_16&doctype=Standard&book=B -URIDate 2017-03-09 + Details
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- References No definition available. + Details
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- Definition The decrease in an allowance account for credit losses of financial assets resulting from the reversal of impairment. [Refer: Allowance account for credit losses of financial assets] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Note Expiry date 2018-01-01 -Name IFRS -Number 7 -IssueDate 2017-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_16&doctype=Standard&book=B -URIDate 2017-03-09 + Details
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- Definition The decrease in an allowance account for credit losses of financial assets resulting from the utilisation of the allowance. [Refer: Allowance account for credit losses of financial assets] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Note Expiry date 2018-01-01 -Name IFRS -Number 7 -IssueDate 2017-01-01 -Paragraph 16 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_16&doctype=Standard&book=B -URIDate 2017-03-09 + Details
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- Details
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