Per Share Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 27, 2019
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Dolby Laboratories, Inc.	$ 310,227	$ 231,363	$ 255,151
Weighted Average Number of Shares Outstanding, Basic	101,190	100,564	101,629
Potential common shares from options to purchase Class A and Class B common stock	1,994	1,400	1,922
Potential common shares from restricted stock units	1,376	941	1,021
Weighted Average Number of Shares Outstanding, Diluted	104,622	102,944	104,572
Basic (usd per share)	$ 3.07	$ 2.30	$ 2.51
Net income per share attributable to Dolby Laboratories, Inc. - Diluted	$ 2.97	$ 2.25	$ 2.44
Incremental Common Shares Attributable To Employee Stock Purchase Plan	62	39	0
Employee Stock [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations	2	1	0
Employee Stock Option [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations	235	3,209	2,340
Restricted Stock Units [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations	48	2	1