Interim Condensed Consolidated Statements Of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Total Dolby Laboratories,Inc.[Member]	Controlling Interest [Member]	Class A Common Stock [Member] Common Stock [Member]	Class A Common Stock [Member] Additional Paid-In Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding		101
Beginning balance at Sep. 29, 2017	$ 2,398,727		$ 61,331	$ 2,337,948	$ (7,753)	$ 2,391,627	$ 7,100
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(53,158)			(53,302)		(53,302)	144
Translation adjustments, net of tax of $829 and $(64), respectively	1,218				1,224	1,224	(6)
Unrealized gains (losses) on available-for-sale securities, net of tax of $(327) and $(98), respectively	(1,593)				(1,593)	(1,593)
Distributions to controlling interest	(1,021)						(1,021)
Stock-based compensation expense	18,684		18,684			18,684
Shares repurchased (in shares)
Repurchase of common stock	(29,993)		(29,993)			(29,993)
Cash dividends declared and paid on common stock	(16,377)			(16,377)		(16,377)
Common stock issued under employee stock plans	41,463		41,462			41,463		$ 1
Tax withholdings on vesting of restricted stock	(18,821)					(18,821)			$ (18,821)
Ending balance at Dec. 29, 2017	2,339,129		72,663	2,268,269	(8,122)	2,332,912	6,217
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding		102
Shares, Outstanding		102
Beginning balance at Sep. 28, 2018	2,370,503		66,127	2,313,539	(15,832)	2,363,936	6,567
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	98,358			98,219		98,219	139
Translation adjustments, net of tax of $829 and $(64), respectively	(3,728)				(3,577)	(3,577)	(151)
Unrealized gains (losses) on available-for-sale securities, net of tax of $(327) and $(98), respectively	770				770	770
Distributions to controlling interest	(906)						(906)
Stock-based compensation expense	21,482		21,482			21,482
Shares repurchased (in shares)
Repurchase of common stock	(112,545)		(82,203)	30,342		(112,545)
Cash dividends declared and paid on common stock	(19,573)			(19,573)		(19,573)
Tax benefit/(deficiency) from the stock incentive plans
Common stock issued under employee stock plans	14,272		14,272			14,272
Tax withholdings on vesting of restricted stock	(19,679)					(19,679)		$ (1)	$ (19,678)
Ending balance at Dec. 28, 2018	$ 2,348,954		$ 0	$ 2,361,843	$ (18,639)	$ 2,343,305	$ 5,649
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding		101