Consolidated Statements Of Stockholders' Equity - USD ($) $ in Thousands		Total	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Total Dolby Laboratories,Inc.[Member]	Controlling Interest [Member]	Class B Common Stock [Member] Common Stock [Member]	Common Class A [Member] Common Stock [Member]
Cumulative effect of the adoption | Accounting Standards Update 2014-09		$ 250,200
Beginning balance, shares at Sep. 30, 2016								44,404,000	57,018,000
Beginning balance, value at Sep. 30, 2016	[1]	2,228,941	$ 42,032	$ 2,188,526	$ (10,197)	$ 2,220,462	$ 8,479	$ 44	$ 57
Net income		207,106		206,481		206,481	625
Translation adjustments, net of taxes		3,653			2,444	2,444	90
Other comprehensive income, net of tax		2,534
Unrealized gains/(losses) on available-for-sale securities, net of tax		(1,119)
Distributions to controlling interest		(2,094)					2,094
Stock-based compensation expense		65,343	65,343			65,343
Repurchase of common stock, shares									2,025,000
Repurchase of common stock, value		(100,000)	99,998			100,000			$ 2
Cash dividends declared and paid on common stock		(57,059)		(57,059)		(57,059)
Tax benefit/(deficiency) from the stock incentive plans		(1,634)	(1,634)			(1,634)
Class A common stock issued under employee stock plans, shares									3,138,000
Class A common stock issued under employee stock plans, value		69,998	69,996			69,998			$ 2
Shares repurchased for tax witholdings on vesting of restricted stock, shares									379,000
Shares repurchased for tax witholdings on vesting of restricted stock, value		(17,676)	(17,676)			(17,676)			$ 0
Transfer of Class B common stock to Class A common stock, shares								1,530,000	(1,530,000)
Transfer of Class B common stock to Class A common stock, value								$ 1	$ (1)
Ending balance, shares at Sep. 29, 2017								42,874,000	59,282,000
Ending balance, value at Sep. 29, 2017		2,398,727	61,331	2,337,948	(7,753)	2,391,627	7,100	$ 43	$ 58
Net income		42,305		41,746		41,746	559
Translation adjustments, net of taxes		(5,578)			(8,079)	(8,079)	(70)
Other comprehensive income, net of tax		(8,149)
Unrealized gains/(losses) on available-for-sale securities, net of tax		(2,571)
Distributions to controlling interest		(1,022)					1,022
Stock-based compensation expense		71,249	71,249			71,249
Repurchase of common stock, shares									2,381,000
Repurchase of common stock, value		(150,470)	150,468			150,470			$ 2
Cash dividends declared and paid on common stock		(66,155)		(66,155)		(66,155)
Tax benefit/(deficiency) from the stock incentive plans		0	0			0
Class A common stock issued under employee stock plans, shares									3,823,000
Class A common stock issued under employee stock plans, value		106,162	106,159			106,162			$ 3
Shares repurchased for tax witholdings on vesting of restricted stock, shares									358,000
Shares repurchased for tax witholdings on vesting of restricted stock, value		(22,144)	(22,144)			(22,144)			$ 0
Transfer of Class B common stock to Class A common stock, shares								3,613,000	(3,613,000)
Transfer of Class B common stock to Class A common stock, value								$ 2	$ (2)
Ending balance, shares at Sep. 28, 2018								39,261,000	63,979,000
Ending balance, value at Sep. 28, 2018		2,370,503	66,127	2,313,539	(15,832)	2,363,936	6,567	$ 41	$ 61
Net income		255,505		255,151		255,151	354
Translation adjustments, net of taxes		(10,166)			(4,793)	(4,793)	(227)
Other comprehensive income, net of tax		(5,020)
Unrealized gains/(losses) on available-for-sale securities, net of tax		5,146
Distributions to controlling interest		(1,015)					1,015
Stock-based compensation expense		$ 76,580	76,580			76,580
Repurchase of common stock, shares		(5,267,609)							5,268,000
Repurchase of common stock, value		$ (340,585)	177,264	(163,317)		340,585			$ 4
Cash dividends declared and paid on common stock		(77,496)		(77,496)		(77,496)
Tax benefit/(deficiency) from the stock incentive plans		0	0			0
Class A common stock issued under employee stock plans, shares									2,514,000
Class A common stock issued under employee stock plans, value		57,346	57,345			57,346			$ 1
Shares repurchased for tax witholdings on vesting of restricted stock, shares									345,000
Shares repurchased for tax witholdings on vesting of restricted stock, value		(22,788)	(22,788)			(22,788)			$ 0
Transfer of Class B common stock to Class A common stock, shares								3,031,000	(3,031,000)
Transfer of Class B common stock to Class A common stock, value								$ 0	$ 0
Ending balance, shares at Sep. 27, 2019								36,230,000	63,911,000
Ending balance, value at Sep. 27, 2019		$ 2,313,030	$ 0	$ 2,327,877	$ (20,625)	$ 2,307,351	$ 5,679	$ 41	$ 58

[1] The cumulative effect of the adoption of ASU 2014-09, Revenue from Contracts with Customers ("ASC 606") resulted in an adjustment to retained earnings of $250.2 million as of September 30, 2016.