Per Share Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 29, 2019	Mar. 30, 2018	Mar. 29, 2019	Mar. 30, 2018
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income attributable to Dolby Laboratories, Inc.	$ 73,440	$ 65,216	$ 171,659	$ 11,914
Weighted average shares outstanding-basic (in shares)	102,141	103,771	102,409	103,162
Potential common shares from options to purchase common stock (in shares)	1,943	2,397	2,096	2,428
Potential common shares from restricted stock units (in shares)	503	833	1,024	1,215
Weighted average shares outstanding-diluted (in shares)	104,587	107,001	105,529	106,805
Net income per share attributable to Dolby Laboratories, Inc. - Basic (in usd per share)	$ 0.72	$ 0.63	$ 1.68	$ 0.12
Net income per share attributable to Dolby Laboratories, Inc. - Diluted (in usd per share)	$ 0.70	$ 0.61	$ 1.63	$ 0.11
Employee Stock Option [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	2,647	1,276	2,110	768
Restricted Stock Units (RSUs) [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations (in shares)	22	3	15	7