Financial Risk Management Objectives and Policies - Gains and Losses from Cash Flow Hedges (Details) - EUR (€) € in Thousands	12 Months Ended
Sep. 30, 2024	Sep. 30, 2023
Disclosure of detailed information about financial instruments [abstract]
Recognized in equity	€ 345	€ (345)
Due to early discontinuation of the hedging relationship	549
Due to realization of the hedged item	€ 1,224	€ 272

Gains (losses) on ineffectiveness of cash flow hedges recognised in profit or loss due to early discontinuation of the hedging relationship

No definition available.

Name:	birk_GainsLossesOnIneffectivenessOfCashFlowHedgesRecognisedInProfitOrLossDueToEarlyDiscontinuationOfTheHedgingRelationship
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration