Derivative Instruments and Hedging Activities (Notional and Fair Value) (Details) (USD $) In Thousands, unless otherwise specified							9 Months Ended
Jun. 29, 2013 Euro currency hedge contracts	Sep. 29, 2012 Euro currency hedge contracts	Jun. 29, 2013 Korea (South), Won	Sep. 29, 2012 Korea (South), Won	Jun. 29, 2013 Other foreign currency hedge contracts	Sep. 29, 2012 Other foreign currency hedge contracts	Jun. 29, 2013 Forward contracts Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Maximum maturities of foreign currency derivative instruments (in months)							3 months
U.S. Notional Contract Value, Purchase	$ 43,696	$ 61,779			$ 1,471	$ 0
U.S. Notional Fair Value, Purchase	43,115	62,404			1,463	0
U.S. Notional Contract Value, Sell			(12,929)	(39,039)	(23,483)	(20,452)
U.S. Notional Fair Value, Sell			$ (12,872)	$ (39,559)	$ (23,590)	$ (20,578)

Notional Fair Value Amount Of Foreign Currency Derivative Purchase Contracts

No definition available.

Name:	cohr_NotionalFairValueAmountOfForeignCurrencyDerivativePurchaseContracts
Namespace Prefix:	cohr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Notional Fair Value Amount Of Foreign Currency Derivative Sales Contracts

+ References

No definition available.

+ Details

Name:	cohr_NotionalFairValueAmountOfForeignCurrencyDerivativeSalesContracts
Namespace Prefix:	cohr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Definition

Maximum amount of time remaining before foreign currency exchange rate derivatives mature or expire, 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_MaximumRemainingMaturityOfForeignCurrencyDerivatives1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate notional amount of foreign currency derivatives to purchase a foreign currency. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959

+ Details

Name:	us-gaap_NotionalAmountOfForeignCurrencyDerivativePurchaseContracts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Aggregate notional amount of foreign currency derivatives to sell a foreign currency. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

+ References

+ Details

Name:	us-gaap_NotionalAmountOfForeignCurrencyDerivativeSaleContracts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant