Per Share Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Dolby Laboratories, Inc.	$ 83,145	$ 76,043	$ 72,154	$ 180,007
Weighted average shares outstanding-basic (in shares)	103,836	101,905	103,386	101,725
Potential common shares from options to purchase common stock (in shares)	2,198	1,571	2,364	1,494
Potential common shares from restricted stock units (in shares)	916	746	1,193	767
Weighted average shares outstanding-diluted (in shares)	106,950	104,222	106,943	103,986
Net income per share attributable to Dolby Laboratories, Inc. - Basic (in usd per share)	$ 0.80	$ 0.75	$ 0.70	$ 1.77
Net income per share attributable to Dolby Laboratories, Inc. - Diluted (in usd per share)	$ 0.78	$ 0.73	$ 0.67	$ 1.73
Employee Stock Option [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	1,292	1,757	950	1,429
Restricted Stock Units (RSUs) [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	44	0	16	10