v2.3.0.15

Commitments And Contingencies (Narrative) (USD $) In Millions	12 Months Ended
	Sep. 30, 2011	Sep. 24, 2010	Sep. 25, 2009
Commitments And Contingencies [Abstract]
Rental expenses under operating leases	$ 12.6	$ 8.7	$ 7.9
Expense for rent paid to principal stockholder	$ 1.4	$ 1.4	$ 1.3

X

- Definition

Expense for rent paid to principal stockholder.

+ Details

Name:	dlb_ExpenseForRentPaidToPrincipalStockholder
Namespace Prefix:	dlb
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	us-gaap_CommitmentsAndContingenciesDisclosureAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

+ Details

Name:	us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration