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LONG-TERM INCENTIVE PLANS - Exercise of stock options (Details) - Stock options | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 BRL (R$) Options item | Dec. 31, 2016 BRL (R$) Options | Dec. 31, 2015 BRL (R$) Options | Dec. 31, 2014 BRL (R$) Options
Exercise price of options |  |  |  |
Quantity (in shares) | Options | 292,391 | 569,115 | 1,074,246 | 2,448,973
Average exercise price | R$ 17.91 | R$ 16.64 | R$ 18.36 | R$ 19.53
Number exercisable at end of the period (in shares) | Options | 57,668 | 57,678 | 127,899 |
Expense from equity-settled long-term incentive plan - recognized directly in equity | R$ 25,403,000 | R$ 38,023,000 | R$ 39,657,000 |
Options granted (in shares) | item | 0 |  |  |
R$ 14.39 |  |  |  |
Exercise price of options |  |  |  |
Exercise price | R$ 14.39 |  |  |
Quantity (in shares) | Options | 40,873 |  |  |
Average period of grace (in years) | item | 1.2 |  |  |
Average exercise price | R$ 13.89 |  |  |
Number exercisable at end of the period (in shares) | Options | 40,873 |  |  |
R$ 10.58 to R$ 29.12 |  |  |  |
Exercise price of options |  |  |  |
Quantity (in shares) | Options | 251,518 |  |  |
Average period of grace (in years) | item | 5.0 |  |  |
Average exercise price | R$ 18.56 |  |  |
Number exercisable at end of the period (in shares) | Options | 16,795 |  |  |
R$ 10.58 to R$ 29.12 | Minimum |  |  |  |
Exercise price of options |  |  |  |
Exercise price | R$ 10.58 |  |  |
R$ 10.58 to R$ 29.12 | Maximum |  |  |  |
Exercise price of options |  |  |  |
Exercise price | R$ 29.12 |  |  |

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- Definition The amount of expense arising from equity-settled share-based payment transactions in which the goods or services received did not qualify for recognition as assets. [Refer: Expense from share-based payment transactions in which goods or services received did not qualify for recognition as assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2017-01-01 -Paragraph 51 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_51_a&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The number of share options outstanding in a share-based payment arrangement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2017-01-01 -Paragraph 45 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_45_d&doctype=Standard -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2017-01-01 -Paragraph 45 -Subparagraph b -Clause i -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_45_b_i&doctype=Standard -URIDate 2017-03-09 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2017-01-01 -Paragraph 45 -Subparagraph b -Clause vi -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_45_b_vi&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition The weighted average exercise price of share options outstanding in a share-based payment arrangement. [Refer: Weighted average [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2017-01-01 -Paragraph 45 -Subparagraph b -Clause i -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_45_b_i&doctype=Standard -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2017-01-01 -Paragraph 45 -Subparagraph b -Clause vi -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_45_b_vi&doctype=Standard -URIDate 2017-03-09 + Details
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