Composition Of Certain Financial Statement Captions (Schedule Of Other Non-Current Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2012	Sep. 30, 2011
Composition Of Certain Financial Statement Captions [Abstract]
Supplemental retirement plan obligations	$ 2,039	$ 1,811
Non-current tax liabilities	19,499	13,070
Other liabilities	9,907	8,574
Other non-current liabilities	$ 31,445	$ 23,455

Name:	dlb_CompositionOfCertainFinancialStatementCaptionsAbstract
Namespace Prefix:	dlb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Non-Current Tax Liabilities

+ References

No definition available.

+ Details

Name:	dlb_NonCurrentTaxLiabilities
Namespace Prefix:	dlb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The aggregate carrying amount, as of the balance sheet date, of liabilities not separately disclosed in the balance sheet.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 9

-Section 03

-Paragraph 15

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_OtherLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Aggregate carrying amount, as of the balance sheet date, of noncurrent obligations not separately disclosed in the balance sheet. Noncurrent liabilities are expected to be paid after one year (or the normal operating cycle, if longer).

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 24

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.24)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_OtherLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The total amount of the entity's noncurrent obligation as of the balance sheet date under any other retirement plan(s), such as one or more defined contribution plans.

+ References

No definition available.

+ Details

Name:	us-gaap_OtherPostretirementBenefitsPayableNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant