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. 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
Quarterly Financial Data [Abstract]
Licensing	$ 203,325	$ 204,855	$ 243,333	$ 216,598	$ 208,943	$ 205,625	$ 258,616	$ 205,660	$ 868,111	$ 878,844	$ 807,081
Products	25,060	22,596	22,985	13,263	13,581	12,971	14,563	18,104	83,904	59,219	80,603
Services	4,363	4,251	5,632	4,377	4,433	4,754	5,413	7,513	18,623	22,113	21,990
Total revenue	232,748	231,702	271,950	234,238	226,957	223,350	278,592	231,277	970,638	960,176	909,674
Cost of revenue	25,377	24,880	25,149	19,410	12,420	18,869	17,505	21,382	94,816	70,176	96,719
Gross margin	207,371	206,822	246,801	214,828	214,537	204,481	261,087	209,895	875,822	890,000	812,955
Income before taxes and controlling interest	64,203	47,378	79,885	54,316	60,662	51,814	102,922	60,701	245,782	276,099	250,646
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
Net Income Per Share:
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
Diluted (usd per share)	$ 0.45	$ 0.34	$ 0.56	$ 0.40	$ 0.44	$ 0.38	$ 0.73	$ 0.43	$ 1.75	$ 1.99	$ 1.84
Weighted-average shares outstanding:
Basic (shares)	101,935	102,670	102,509	102,303	102,211	102,350	102,291	101,750	102,354	102,151	101,879
Diluted (shares)	103,059	104,105	103,904	104,275	104,116	103,942	103,934	103,192	103,862	103,632	102,788