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	162,323			161,927		161,927	396
Translation adjustments, net of tax of $829 and $(64), respectively	(753)				(147)	(147)	(606)
Unrealized gains (losses) on available-for-sale securities, net of tax of $(327) and $(98), respectively	1,404				1,404	1,404
Distributions to controlling interest	(214)						(214)
Stock-based compensation expense	51,473		51,473			51,473
Repurchase of common stock	(84,854)	(2)	(84,852)	0		(84,854)
Cash dividends declared and paid on common stock	(36,256)			(36,256)		(36,256)
Tax benefit/(deficiency) from the stock incentive plans	(724)		(724)			(724)
Common stock issued under employee stock plans	44,068	2	44,066			44,068
Tax withholdings on vesting of restricted stock	(12,154)	0	(12,154)			(12,154)
Ending balance at Jul. 01, 2016	1,940,320	102	15,380	1,926,528	(10,205)	1,931,805	8,515
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	180,487			180,007		180,007	480
Translation adjustments, net of tax of $829 and $(64), respectively	(12)				42	42	(54)
Unrealized gains (losses) on available-for-sale securities, net of tax of $(327) and $(98), respectively	(1,363)				(1,363)	(1,363)
Distributions to controlling interest	(2,094)			0			(2,094)
Stock-based compensation expense	48,940		48,940			48,940
Repurchase of common stock	(74,994)	(2)	(74,992)	0		(74,994)
Cash dividends declared and paid on common stock	(42,768)			(42,768)		(42,768)
Tax benefit/(deficiency) from the stock incentive plans	4,558		4,558			4,558
Common stock issued under employee stock plans	47,765	2	47,763			47,765
Tax withholdings on vesting of restricted stock	(16,875)	0	(16,875)			(16,875)
Ending balance at Jun. 30, 2017	$ 2,122,379	$ 101	$ 51,426	$ 2,075,559	$ (11,518)	$ 2,115,568	$ 6,811