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LONG-TERM INCENTIVE PLANS - Restricted Shares and Performance Shares (Details) - Restricted Shares and Performance Shares R$ in Thousands | 12 Months Ended
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Dec. 31, 2018 BRL (R$) EquityInstruments shares | Dec. 31, 2017 BRL (R$) EquityInstruments | Dec. 31, 2016 EquityInstruments
LONG-TERM INCENTIVE PLANS |  |  |
Balance, beginning of year | 18,975,084 | 20,433,491 | 12,525,256
Granted | 2,411,345 | 3,170,952 | 13,357,922
Cancelled | (3,150,635) | (1,901,782) | (3,046,593)
Exercised | (3,974,293) | (2,727,577) | (2,403,094)
Balance, end of year | 14,261,501 | 18,975,084 | 20,433,491
Expense from equity-settled long-term incentive plan | R$ | R$ 41,186 | R$ 25,403 |
Grace period |  | 3 years | 5 years
Preferred shares |  |  |
LONG-TERM INCENTIVE PLANS |  |  |
Treasury shares | shares | 21,797,490 |  |

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- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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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 2018-01-01 -Paragraph 51 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2018-03-01&anchor=para_51_a&doctype=Standard -URIDate 2018-03-16 + Details
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- Definition The number of other equity instruments (ie other than share options) granted in a share-based payment arrangement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 2 -IssueDate 2018-01-01 -Paragraph 47 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2018-03-01&anchor=para_47_b&doctype=Standard -URIDate 2018-03-16 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name IFRS -Number 2 -IssueDate 2018-01-01 -Paragraph 45 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2018-03-01&anchor=para_45&doctype=Standard -URIDate 2018-03-16 + Details
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