Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Related party rent expense	$ 3,483	$ 3,142	$ 3,097
Dolby Properties Brisbane, LLC [Member]
Ownership interest (percent)	49.00%
Dolby Properties Burbank, LLC [Member]
Ownership interest (percent)	49.00%
Dolby Properties United Kingdom, LLC [Member]
Ownership interest (percent)	49.00%
Dolby Properties, LP [Member]
Ownership interest (percent)	10.00%