Commitments and Contingencies Other Contingencies (Details) € in Millions	12 Months Ended
Oct. 03, 2020 EUR (€)
Commitments and Contingencies Disclosure [Abstract]
German government export compliance matter impacted transactions	€ 1.5

German government export compliance matter impacted transactions

No definition available.

Name:	cohr_Germangovernmentexportcompliancematterimpactedtransactions
Namespace Prefix:	cohr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration