v2.3.0.15

Commitments And Contingencies (Narrative) (USD $) In Millions | 12 Months Ended
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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

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- 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

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

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- 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