Selected Quarterly Financial Data (unaudited) (Schedule Of Selected Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Sep. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Quarterly Financial Data [Abstract]
Licensing	$ 213,370	$ 278,106	$ 241,617	$ 232,699	$ 203,541	$ 253,026	$ 249,336	$ 211,129	$ 965,792	$ 917,032	$ 868,111
Products	23,797	22,569	20,713	28,211	25,033	20,638	20,063	24,809	95,290	90,543	83,904
Services	4,881	4,990	5,144	5,357	4,423	3,923	4,941	4,876	20,372	18,163	18,623
Total revenue	242,048	305,665	267,474	266,267	232,997	277,587	274,340	240,814	1,081,454	1,025,738	970,638
Cost of revenue	29,238	32,125	26,977	29,967	30,222	24,621	24,373	29,766	118,307	108,982	94,816
Gross margin	212,810	273,540	240,497	236,300	202,775	252,966	249,967	211,048	963,147	916,756	875,822
Income before taxes and controlling interest	26,491	96,303	66,194	67,656	30,813	81,784	83,823	39,484	256,644	235,904	245,782
Net income attributable to Dolby Laboratories, Inc.	$ 21,795	$ 76,043	$ 50,590	$ 53,374	$ 23,933	$ 63,628	$ 67,398	$ 30,901	$ 201,802	$ 185,860	$ 181,390
Net Income Per Share:
Basic (usd per share)	$ 0.21	$ 0.75	$ 0.50	$ 0.53	$ 0.24	$ 0.63	$ 0.67	$ 0.31	$ 1.98	$ 1.85	$ 1.77
Diluted (usd per share)	$ 0.21	$ 0.73	$ 0.49	$ 0.51	$ 0.23	$ 0.62	$ 0.66	$ 0.30	$ 1.95	$ 1.81	$ 1.75
Weighted-average shares outstanding:
Basic (shares)	101,959	101,905	101,787	101,483	101,145	100,533	100,456	100,734	101,784	100,717	102,354
Diluted (shares)	103,530	104,222	103,883	103,876	103,766	102,677	101,555	101,931	103,286	102,424	103,862