v2.3.0.15

Summary Of Significant Accounting Policies (Tables) | 12 Months Ended
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Sep. 30, 2011
Summary Of Significant Accounting Policies [Abstract] |
Schedule Of Property, Plant, And Equipment, Estimated Useful Life |
Systems and software |  | 3to 5 years
Machinery and equipment |  | 3to 8 years
Furniture and fixtures |  | 5to 8 years
Leasehold improvements |  | Lesser of useful life or related lease term
Buildings |  | Up to 40 years

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- Definition Property Plant And Equipment Estimated Useful Life [Table Text Block] + Details
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Namespace Prefix: | dlb
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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