Other disclosures (Details 2) - BRL (R$) R$ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Offbalance Funds Under Management [Abstract]
Funds under management	R$ 1,747,623	R$ 1,533,620	R$ 2,542,286
Total	R$ 1,747,623	R$ 1,533,620	R$ 2,542,286

The amount that investment funds constitute of the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [member]; Investment funds [member]]

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 19
-IssueDate 2017-01-01
-Paragraph 142
-Subparagraph f
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_142_f&doctype=Standard
-URIDate 2017-03-09

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