Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e1043-128460

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585

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Balance Type:	credit
Period Type:	duration

- Details

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- Details

Name:	us-gaap_BusinessAcquisitionAxis=cohr_O.R.LasertechnologiesGmbHMember
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- Details

Name:	us-gaap_BusinessAcquisitionAxis=cohr_OndaxIncMember
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Data Type:	na
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- Details

Name:	us-gaap_BusinessAcquisitionAxis=cohr_QuantumCoatingIncMember
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Business Combinations - Additional Information (Details) - USD ($) $ in Millions			12 Months Ended
	Oct. 05, 2018	Mar. 08, 2018	Oct. 03, 2020	Sep. 28, 2019
Minimum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life			4 years
Maximum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life			15 years
O.R. Laser
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 47.4
Expensed acquisition-related costs				$ 0.6
O.R. Laser \| Minimum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life		1 year
O.R. Laser \| Maximum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life		8 years
Ondax Inc.
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 12.0
Ondax Inc. \| Minimum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life	1 year
Ondax Inc. \| Maximum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life	8 years
Quantum Coating, Inc.
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 7.0
Quantum Coating, Inc. \| Minimum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life	1 year
Quantum Coating, Inc. \| Maximum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life	5 years