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Financial Instruments and Risk Management - Summary of Derivative Instruments Contracted (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2017 BRL (R$)
Derivative financial instruments [Abstract]
Swap operation floor rate	R$ 3.25
Swap ceiling rate	R$ 5
FX Variation Interest rate	9.25%

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- Definition

Derivative financial instruments [Abstract]

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No definition available.

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- Definition

FX Variation Interest rate

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No definition available.

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- Definition

Swap ceiling rate

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No definition available.

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- Definition

Swap operation floor rate

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No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration