Interim Condensed Consolidated Statements Of Stockholders' Equity - USD ($) $ 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		101,000
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	12,192			11,914		11,914	278
Translation adjustments, net of tax of $829 and $(64), respectively	5,482				5,289	5,289	193
Unrealized gains (losses) on available-for-sale securities, net of tax of $(327) and $(98), respectively	(3,152)				(3,152)	(3,152)
Distributions to controlling interest	(1,022)						(1,022)
Stock-based compensation expense	36,375		36,375			36,375
Shares repurchased (in shares)								(1,000)
Repurchase of common stock	(34,993)		(34,992)			(34,993)
Cash dividends declared and paid on common stock	(32,956)			(32,956)		(32,956)
Common stock issued under employee stock plans	71,061		71,059			71,061		$ 2
Tax withholdings on vesting of restricted stock	(19,946)					(19,946)			$ (19,946)
Ending balance at Mar. 30, 2018	2,431,768		113,827	2,316,906	(5,616)	2,425,219	6,549
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding		102,000
Shares, Outstanding		102,000
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	171,933			171,659		171,659	274
Translation adjustments, net of tax of $829 and $(64), respectively	(1,713)				(1,719)	(1,719)	6
Unrealized gains (losses) on available-for-sale securities, net of tax of $(327) and $(98), respectively	2,868				2,868	2,868
Distributions to controlling interest	(1,014)						(1,014)
Stock-based compensation expense	$ 40,717		40,717			40,717
Shares repurchased (in shares)	(2,960,357)							(3,000)
Repurchase of common stock	$ (197,880)		(113,321)	84,556		(197,880)
Cash dividends declared and paid on common stock	(39,035)			(39,035)		(39,035)
Tax benefit/(deficiency) from the stock incentive plans
Common stock issued under employee stock plans	27,158		27,157			27,158		$ 1
Tax withholdings on vesting of restricted stock	(20,680)					(20,680)			$ (20,680)
Ending balance at Mar. 29, 2019	$ 2,352,857		$ 0	$ 2,361,607	$ (14,683)	$ 2,347,024	$ 5,833
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares, Outstanding		100,000