Per Share Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 25, 2020
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Dolby Laboratories, Inc.	$ 80,014	$ 135,198
Weighted average shares outstanding-basic (in shares)	101,230	100,716
Potential common shares from options to purchase common stock (in shares)	1,348	1,767
Potential common shares from restricted stock units (in shares)	1,201	1,309
Potential common shares from ESPP (in shares)	22	84
Weighted average shares outstanding-diluted (in shares)	103,801	103,876
Net income per share attributable to Dolby Laboratories, Inc. - Basic (in usd per share)	$ 0.79	$ 1.34
Net income per share attributable to Dolby Laboratories, Inc. - Diluted (in usd per share)	$ 0.77	$ 1.30
Employee Stock Option [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	413	39
Restricted Stock Units (RSUs) [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	203	162
Employee Stock Purchase Plan [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	15	1