Note receivables (Details 2) (Detail) - BRL (R$) R$ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Maturity analysis of note receivables
Receivables	R$ 4,883,321	R$ 3,522,349	R$ 1,715,514
Due within 30 days
Maturity analysis of note receivables
Receivables	2,647,347	2,213,929	970,086
Due within 31 to 120 days
Maturity analysis of note receivables
Receivables	1,763,293	1,045,825	609,689
Due within 121 to 180 days
Maturity analysis of note receivables
Receivables	140,265	114,953	43,144
Due within 181 to 360 days
Maturity analysis of note receivables
Receivables	R$ 332,416	R$ 147,642	R$ 92,595

The amount of non-derivative financial assets with fixed or determinable payments that are not quoted in an active market, other than: (a) those that the entity intends to sell immediately or in the near term, which shall be classified as held for trading, and those that the entity, upon initial recognition, designates as at fair value through profit or loss; (b) those that the entity, upon initial recognition, designates as available for sale; or (c) those for which the holder may not recover substantially all of its initial investment, other than because of credit deterioration, which shall be classified as available for sale. An interest acquired in a pool of assets that are not loans or receivables (for example, an interest in a mutual fund or a similar fund) is not a loan or receivable. [Refer: Derivative financial assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 8
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_8_c&doctype=Standard&book=B
-URIDate 2017-03-09

Name:	ifrs-full_LoansAndReceivables
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant