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]
Beginning balance at Sep. 25, 2015	$ 1,816,007	$ 102	$ 17,571	$ 1,800,857	$ (11,462)	$ 1,807,068	$ 8,939
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	98,556			98,299		98,299	257
Translation adjustments, net of tax of $829 and $(64), respectively	2,122				2,417	2,417	(295)
Unrealized gains (losses) on available-for-sale securities, net of tax of $(327) and $(98), respectively	703				703	703
Distributions to controlling interest	(214)						(214)
Stock-based compensation expense	35,466		35,466			35,466
Repurchase of common stock	(76,856)	(2)	(55,500)	21,354		(76,856)
Cash dividends declared and paid on common stock	(24,200)			(24,200)		(24,200)
Tax benefit/(deficiency) from the stock incentive plans	(1,369)		(1,369)			(1,369)
Common stock issued under employee stock plans	14,575	0	14,575			14,575
Tax withholdings on vesting of restricted stock	(10,742)	(1)	(10,743)			(10,742)
Ending balance at Apr. 01, 2016	1,854,048	101	0	1,853,602	(8,342)	1,845,361	8,687
Beginning balance at Sep. 30, 2016	1,978,735	101	42,032	1,938,320	(10,197)	1,970,256	8,479
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	104,301			103,964		103,964	337
Translation adjustments, net of tax of $829 and $(64), respectively	(3,279)				(3,073)	(3,073)	(206)
Unrealized gains (losses) on available-for-sale securities, net of tax of $(327) and $(98), respectively	(1,438)				(1,438)	(1,438)
Distributions to controlling interest	(2,094)			0			(2,094)
Stock-based compensation expense	33,198		33,198			33,198
Repurchase of common stock	(50,000)	(1)	(49,999)	0		(50,000)
Cash dividends declared and paid on common stock	(28,494)			(28,494)		(28,494)
Tax benefit/(deficiency) from the stock incentive plans	3,818		3,818			3,818
Common stock issued under employee stock plans	24,210	2	24,208			24,210
Tax withholdings on vesting of restricted stock	(15,799)	(1)	(15,798)			(15,799)
Ending balance at Mar. 31, 2017	$ 2,043,158	$ 101	$ 37,459	$ 2,013,790	$ (14,708)	$ 2,036,642	$ 6,516