Per Share Data (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 25, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014	Dec. 27, 2013	Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Document Period End Date									Sep. 25, 2015
Net income attributable to Dolby Laboratories, Inc.	$ 46,553	$ 35,506	$ 57,974	$ 41,357	$ 45,941	$ 39,779	$ 75,868	$ 44,515	$ 181,390	$ 206,103	$ 189,271
Weighted Average Number of Shares Outstanding, Basic	101,935	102,670	102,509	102,303	102,211	102,350	102,291	101,750	102,354	102,151	101,879
Potential common shares from options to purchase Class A and Class B common stock									811	582	287
Potential common shares from restricted stock units									697	899	622
Weighted Average Number of Shares Outstanding, Diluted	103,059	104,105	103,904	104,275	104,116	103,942	103,934	103,192	103,862	103,632	102,788
Basic (usd per share)	$ 0.46	$ 0.35	$ 0.57	$ 0.40	$ 0.45	$ 0.39	$ 0.74	$ 0.44	$ 1.77	$ 2.02	$ 1.86
Net income per share attributable to Dolby Laboratories, Inc. - Diluted	$ 0.45	$ 0.34	$ 0.56	$ 0.40	$ 0.44	$ 0.38	$ 0.73	$ 0.43	$ 1.75	$ 1.99	$ 1.84
Stock Options [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations									4,270	3,987	5,348
Restricted Stock Units [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive securities, excluded from calculations									127	1,835	1,817