Additional Euro currency rate

No definition available.

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- Definition

Additional base rate

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
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- Definition

Additional sources of cash available

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortization period of the debt issuance cost

+ References

No definition available.

+ Details

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- Definition

Applicable margin for Eurocurrency rate loan

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
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- Definition

Applicable margin for base rate revolving loan

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
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- Definition

Base rate range after 1st year

+ References

No definition available.

+ Details

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- Definition

Borrowed under forward contract purchased for the term loan

+ References

No definition available.

+ Details

Name:	cohr_Borrowedunderforwardcontractpurchasedforthetermloan
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Commitment fee accrues range on unused portion of revolving loan

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Interest Rate, Stepdown

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

debt issuance cost amortization period

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
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- Definition

domesticlineofcreditdrawn

+ References

No definition available.

+ Details

Name:	cohr_Domesticlineofcreditdrawn
Namespace Prefix:	cohr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

forward contract purchased for the term loan

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Quarter principal payment requirement for Euro term loan

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
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- Definition

Revolving facility to finance acquisition of Rofin

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Revolving facility to finance acquisition of Rofin, outstanding balance

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Senior secured net leverage ratio to maintain compliance on the loan each quarter end

+ References

No definition available.

+ Details

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- Definition

Swing line, maximum borrowing capacity

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the charge against earnings during the period for commitment fees and debt issuance expenses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

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.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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- Details

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Borrowings (Details) € in Millions		3 Months Ended	12 Months Ended
Borrowings (Details) € in Millions	May 08, 2018	Apr. 01, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jul. 04, 2020 EUR (€)	Jul. 04, 2020 USD ($)	Nov. 07, 2016 EUR (€)	Nov. 07, 2016 USD ($)
Debt [Line Items]
Additional sources of cash available					$ 16,400,000
Debt instrument, unused borrowing capacity, amount					13,500,000
Rofin-Sinar
Debt [Line Items]
Lines of credit, maximum borrowing capacity							$ 30,000,000.0
Swing line, maximum borrowing capacity							$ 10,000,000.0
Credit agreement november 7 2016
Debt [Line Items]
Senior secured net leverage ratio to maintain compliance on the loan each quarter end						3.50	3.50
Euro
Debt [Line Items]
Domestic line of credit drawn \| €						€ 10.0
Euro term loan
Debt [Line Items]
Debt Issuance costs for revolving credit facility		$ 28,500,000
Amortization period of the debt issuance cost			7 years
Short-term Debt [Line Items]
Debt Issuance costs for revolving credit facility		28,500,000
Debt Issuance Costs, Gross		$ 500,000
Euro term loan \| Minimum \| Eurodollar
Debt [Line Items]
Debt instrument, interest rate, stepdown	1.25%
Euro term loan \| Euro
Debt [Line Items]
Borrowed under forward contract purchased for the term loan \| €						€ 670.0
Forward contract purchased for the term loan \| €				€ 359.9
Additional euro currency rate						0.010	0.010
Quarter principal payment requirement for euro term loan						0.0025	0.0025
Euro term loan \| Euro \| Minimum
Debt [Line Items]
Applicable margin for eurocurrency rate loan						0.0400	0.0400
Revolving line of credit
Debt [Line Items]
Revolving facility to finance acquisition of rofin							$ 100,000,000.0
Revolving facility to finance acquisition of Rofin, outstanding balance					10,000,000.0
Additional base rate						0.0050	0.0050
Debt Issuance costs for revolving credit facility			$ 2,300,000
debt issuance cost amortization period			5 years
Short-term Debt [Line Items]
Debt Issuance costs for revolving credit facility			$ 2,300,000
Revolving line of credit \| Minimum
Debt [Line Items]
Base rate range after 1st year						0.0225	0.0225
Applicable margin for base rate revolving loan						0.0300	0.0300
Commitment fee accrues range on unused portion of revolving loan						0.00375	0.00375
Revolving line of credit \| Maximum
Debt [Line Items]
Commitment fee accrues range on unused portion of revolving loan						0.005	0.005
Line of Credit, Foreign \| Europe, other
Debt [Line Items]
Amounts drawn upon line of credit					$ 2,900,000