Securities purchased (sold) under resale (repurchase) agreements - Additional Information (Detail) - BRL (R$) R$ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of securities purchased under agreements to resell [Abstract]
Investments in purchase and sale commitments, interest rate	3.68%	4.63%		6.43%
Securities purchased under agreements to resel	R$ 309,053	R$ 654,057	R$ 133,028	R$ 488,809	R$ 420,958
Securities sold under repurchase agreements, interest rate	364.00%	448.00%		640.00%

The amount of instruments purchased for resale in reverse repurchase agreements and cash collateral on securities borrowed. [Refer: Repurchase agreements and cash collateral on securities lent]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_55&doctype=Standard
-URIDate 2019-03-27

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