Trade Accounts Payable - Additional Information (Detail) - PEN (S/) S/ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Trade Accounts Payable [abstract]
Unbilled services received include the estimate made by Management of the valuation of the percentage of completion	S/ 378.7	S/ 132.5

Unbilled services received include management of valuation of percentage of completion

No definition available.

Name:	gram_UnbilledServicesReceivedIncludeManagementOfValuationOfPercentageOfCompletionAmount
Namespace Prefix:	gram_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant