Summary of Significant Accounting Policies (Schedule of Adoption of ASC 606 Standard) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
		Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 28, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 29, 2017	Sep. 27, 2019	Sep. 28, 2018	Sep. 29, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue										$ 1,241,620	$ 1,054,600	$ 1,080,177
Gross margin		$ 252,867	$ 262,469	$ 301,683	$ 263,747	$ 209,312	$ 180,397	$ 268,695	$ 268,634	1,080,766	927,038	961,648
Provision for income taxes										(26,802)	(154,069)	(48,039)
Net income attributable to Dolby Laboratories, Inc.		$ 43,918	$ 39,574	$ 73,440	$ 98,219	$ 26,716	$ 3,116	$ 65,216	$ (53,302)	$ 255,151	$ 41,746	$ 206,481
Diluted (usd per share)		$ 0.43	$ 0.38	$ 0.70	$ 0.93	$ 0.25	$ 0.03	$ 0.61	$ (0.52)	$ 2.44	$ 0.39	$ 2.00
Accounts receivable, net		$ 189,115				$ 166,133				$ 189,115	$ 166,133
Contract assets		195,651				165,959				195,651	165,959
Prepaid expenses and other current assets		39,704				34,890				39,704	34,890
Deferred taxes		114,075				74,766				114,075	74,766
Other non-current assets		93,395				80,080				93,395	80,080
Accrued liabilities		268,144				243,128				268,144	243,128
Contract liabilities		19,991				17,468				19,991	17,468
Non-current contract liabilities		24,404				25,887				24,404	25,887
Other non-current liabilities		177,462				183,799				177,462	183,799
Retained earnings		$ 2,327,877				2,313,539				2,327,877	2,313,539
Net income including controlling interest										255,505	42,305	$ 207,106
Provision for doubtful accounts										4,523	2,413	924
Deferred income taxes										(40,191)	61,059	(35,046)
Accounts receivable										(27,492)	100,129	(56,559)
Contract assets										(29,708)	(2,502)	(5,519)
Prepaid expenses and other assets										(6,200)	(52,485)	(12,302)
Accounts payable and other liabilities										169	(29,019)	103,505
Contract liabilities										1,084	(59)	4,980
Other non-current liabilities										(13,996)	34,650	381
Net cash provided by operating activities										$ 327,674	352,202	$ 377,793
Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue											1,171,924
Gross margin											1,043,664
Provision for income taxes											(190,062)
Net income attributable to Dolby Laboratories, Inc.											$ 122,246
Diluted (usd per share)											$ 1.14
Accounts receivable, net						137,151					$ 137,151
Contract assets						0					0
Prepaid expenses and other current assets						35,209					35,209
Deferred taxes						101,070					101,070
Other non-current assets						42,280					42,280
Accrued liabilities						223,594					223,594
Contract liabilities						23,931					23,931
Non-current contract liabilities						40,064					40,064
Other non-current liabilities						150,960					150,960
Retained earnings						2,139,154					2,139,154
Net income including controlling interest	[1]										122,805
Provision for doubtful accounts	[1]										2,507
Deferred income taxes	[1]										89,934
Accounts receivable	[1]										(65,723)
Contract assets	[1]										0
Prepaid expenses and other assets	[1]										(14,895)
Accounts payable and other liabilities	[1]										15,690
Contract liabilities	[1]										4,362
Other non-current liabilities	[1]										1,811
Net cash provided by operating activities	[1]										352,202
Restatement Adjustment [Member] | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue											(117,324)
Gross margin											(116,626)
Provision for income taxes											35,993
Net income attributable to Dolby Laboratories, Inc.											$ (80,500)
Diluted (usd per share)											$ (0.75)
Accounts receivable, net						28,982					$ 28,982
Contract assets						165,959					165,959
Prepaid expenses and other current assets						(319)					(319)
Deferred taxes						(26,304)					(26,304)
Other non-current assets						37,800					37,800
Accrued liabilities						19,534					19,534
Contract liabilities						(6,463)					(6,463)
Non-current contract liabilities						(14,177)					(14,177)
Other non-current liabilities						32,839					32,839
Retained earnings						$ 174,385					174,385
Net income including controlling interest											(80,500)
Provision for doubtful accounts											(94)
Deferred income taxes											(28,875)
Accounts receivable											165,852
Contract assets											(2,502)
Prepaid expenses and other assets											(37,590)
Accounts payable and other liabilities											(44,709)
Contract liabilities											(4,421)
Other non-current liabilities											32,839
Net cash provided by operating activities											$ 0

[1] Previously reported statement of cash flows in the table above reflects the adoption of ASU 2016-18. The impact to our previously reported condensed consolidated statement of cash flows is not material. Refer to disclosure below for further detail.