Per Share Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Document Period End Date			Jun. 30, 2017
Net income attributable to Dolby Laboratories, Inc.	$ 76,043	$ 63,628	$ 180,007	$ 161,927
Weighted average shares outstanding-basic	101,905	100,533	101,725	100,578
Potential common shares from options to purchase common stock	1,571	1,372	1,494	839
Potential common shares from restricted stock units	746	772	767	562
Weighted average shares outstanding-diluted	104,222	102,677	103,986	101,979
Net income per share attributable to Dolby Laboratories, Inc. - Basic (in usd per share)	$ 0.75	$ 0.63	$ 1.77	$ 1.61
Net income per share attributable to Dolby Laboratories, Inc. - Diluted (in usd per share)	$ 0.73	$ 0.62	$ 1.73	$ 1.59
Employee Stock Option [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	1,757	2,241	1,429	5,910
Restricted Stock Units (RSUs) [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	0	6	10	13