Per Share Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 26, 2021	Mar. 27, 2020	Mar. 26, 2021	Mar. 27, 2020
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Dolby Laboratories, Inc.	$ 76,217	$ 88,496	$ 211,415	$ 137,249
Weighted average shares outstanding-basic (in shares)	101,464	100,854	101,090	100,595
Potential common shares from options to purchase common stock (in shares)	2,102	1,471	1,980	1,591
Potential common shares from restricted stock units (in shares)	939	408	1,258	905
Potential common shares from ESPP (in shares)	76	40	86	42
Weighted average shares outstanding-diluted (in shares)	104,581	102,773	104,414	103,133
Net income per share attributable to Dolby Laboratories, Inc. - Basic (in usd per share)	$ 0.75	$ 0.88	$ 2.09	$ 1.36
Net income per share attributable to Dolby Laboratories, Inc. - Diluted (in usd per share)	$ 0.73	$ 0.86	$ 2.02	$ 1.33
Employee Stock Option [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	283	3,446	159	3,035
Restricted Stock Units (RSUs) [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	2	72	47	40