FINANCIAL INSTRUMENTS - Measurement of fair value (Details) - BRL (R$) R$ in Thousands	Dec. 31, 2019	Dec. 31, 2018
FINANCIAL INSTRUMENTS
Total financial assets	R$ 4,834,178	R$ 1,750,841
Total financial liabilities	18,988,870	17,339,894
Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Total financial assets	4,834,178	1,750,841
Total financial liabilities	18,988,870	17,123,897
Short-term debts \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial liabilities	1,544,211	1,822,183
Long-term debt \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial liabilities	11,594,612	11,545,658
Debentures
FINANCIAL INSTRUMENTS
Total financial liabilities	2,911,044	1,538,873
Debentures \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial liabilities	18,015	2,755
Non-current financial liabilities	2,893,029	1,536,118
Related parties
FINANCIAL INSTRUMENTS
Total financial liabilities		1,350
Related parties \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial liabilities		1,350
Obligation with FIDC
FINANCIAL INSTRUMENTS
Total financial liabilities	1,018,501	938,526
Obligation with FIDC \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial liabilities	1,018,501	938,526
Unrealized losses on financial instruments - Derivative instruments
FINANCIAL INSTRUMENTS
Total financial liabilities		5,245
Unrealized losses on financial instruments - Derivative instruments \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial liabilities		5,245
Lease liabilities
FINANCIAL INSTRUMENTS
Current financial liabilities	202,536
Non-current financial liabilities	601,733
Other current liabilities
FINANCIAL INSTRUMENTS
Total financial liabilities	666,858	988,967
Other current liabilities \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial liabilities	666,858	772,970
Other non-current liabilities
FINANCIAL INSTRUMENTS
Total financial liabilities	449,375	499,092
Other non-current liabilities \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial liabilities	449,375	499,092
Short-term investments
FINANCIAL INSTRUMENTS
Total financial assets	3,652,949	459,470
Short-term investments \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial assets	3,652,949	459,470
Related parties
FINANCIAL INSTRUMENTS
Total financial assets	95,445	27,939
Total financial liabilities		1,350
Related parties \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial assets	95,445	27,939
Unrealized gains on financial instruments - Derivative instruments
FINANCIAL INSTRUMENTS
Total financial assets	2,846	33,417
Unrealized gains on financial instruments - Derivative instruments \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial assets	2,846	30,711
Non-current financial assets		2,706
Other current assets
FINANCIAL INSTRUMENTS
Total financial assets	618,769	780,423
Other current assets \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial assets	618,769	780,423
Other non-current assets
FINANCIAL INSTRUMENTS
Total financial assets	464,169	449,592
Other non-current assets \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial assets	464,169	449,592
Quoted Prices Active Markets for Identical Assets (Level 1) \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Total financial assets		114,027
Quoted Prices Active Markets for Identical Assets (Level 1) \| Short-term investments \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial assets		114,027
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Total financial assets	4,834,178	1,636,814
Total financial liabilities	18,988,870	17,123,897
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Short-term debts \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial liabilities	1,544,211	1,822,183
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Long-term debt \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial liabilities	11,594,612	11,545,658
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Debentures \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial liabilities	18,015	2,755
Non-current financial liabilities	2,893,029	1,536,118
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Related parties \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial liabilities		1,350
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Obligation with FIDC \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial liabilities	1,018,501	938,526
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Unrealized losses on financial instruments - Derivative instruments \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial liabilities		5,245
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Lease liabilities
FINANCIAL INSTRUMENTS
Current financial liabilities	202,536
Non-current financial liabilities	601,733
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Other current liabilities \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial liabilities	666,858	772,970
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Other non-current liabilities \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial liabilities	449,375	499,092
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Short-term investments \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial assets	3,652,949	345,443
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Related parties \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial assets	95,445	27,939
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Unrealized gains on financial instruments - Derivative instruments \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial assets	2,846	30,711
Non-current financial assets		2,706
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Other current assets \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Current financial assets	618,769	780,423
Quoted Prices in Non-Active Markets for Similar Assets (Level 2) \| Other non-current assets \| Fair Value - Measured at Fair Value on a Recurring Basis
FINANCIAL INSTRUMENTS
Non-current financial assets	R$ 464,169	R$ 449,592

The amount of current financial assets. [Refer: Financial assets]

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The amount of current financial liabilities. [Refer: Financial liabilities]

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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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No definition available.

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The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Financial instruments, class [member]; Financial assets; Derivatives [member]]

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The amount of non-current financial assets. [Refer: Financial assets]

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The amount of non-current financial liabilities. [Refer: Financial liabilities]

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