Income and Social Contribution Taxes - Summary of Reconciliation of Taxes (Detail) - BRL (R$) R$ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income and social contribution taxes details 4 [abstract]
Income (loss) before taxes and share of profit (loss) of joint ventures, and associates	R$ 1,785,818	R$ 2,318,446	R$ 2,227,298
Statutory tax rates	34.00%	34.00%	34.00%
Income and social contribution taxes at the statutory tax rates	R$ (607,178)	R$ (788,272)	R$ (757,281)
Adjustments to the statutory income and social contribution taxes:
Nondeductible expenses	(82,784)	(105,017)	(57,961)
Nontaxable revenues	32,523	19,084	7,561
Adjustment to estimated income	9,706	10,844	14,218
Interest on equity	(538)	(550)	(364)
Unrecorded deferred Income and Social Contribution Taxes Carryforwards deferred	(95,480)
Other adjustments	(2,634)	2,059	6,957
Income and social contribution taxes before tax incentives	(746,385)	(861,852)	(786,870)
Tax incentives-SUDENE	107,666	48,598	98,912
Income and social contribution taxes in the income statement	(638,719)	(813,254)	(687,958)
Current	(476,302)	(922,458)	(800,497)
Deferred	(162,417)	109,204	112,539
Income and social contribution taxes in the income statement	R$ (638,719)	R$ (813,254)	R$ (687,958)
Effective IRPJ and CSLL rates	35.80%	35.10%	30.90%

Adjustments for income tax expense to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Profit (loss)]

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The applicable income tax rate.

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The amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period.

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The amount of tax expense exclusive of income tax expense.

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Adjustment to estimated income.

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Adjustments to statutory income and social contribution taxes.

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The effective income tax and social contribution rates.

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Amount of income and social contribution taxes at statutory tax rates.

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Amount of income and social contribution taxes before tax incentives.

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Amount of Income before taxes and share of profit (loss) of joint ventures, and associates.

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Interest on equity.

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Amount of nontaxable revenues.

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Superintendency of Northeast Development - fiscal incentives focused on the development of the northeastern region of Brazil.

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