Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total		Cumulative effect, period of adoption, adjustment	Common Stock	Capital in Excess of Par Value	Retained Earnings	Retained Earnings Cumulative effect, period of adoption, adjustment	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total Synopsys Stockholders’ Equity	Total Synopsys Stockholders’ Equity Cumulative effect, period of adoption, adjustment	Non-controlling Interest
Balance (in shares) at Oct. 31, 2017				150,445
Beginning balance at Oct. 31, 2017	$ 3,279,724			$ 1,505	$ 1,622,429	$ 2,143,873		$ (426,208)	$ (65,979)	$ 3,275,620		$ 4,104
Beginning balance (Adjustment related to reclassification of certain tax effects from accumulated other comprehensive income (loss)) at Oct. 31, 2017			$ (293)				$ (293)				$ (293)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	432,518					432,518				432,518
Other comprehensive income (loss), net of tax effects	$ (47,198)								(47,198)	(47,198)
Purchases of treasury stock (in shares)	(4,688)	[1]		(4,688)
Purchases of treasury stock, value	$ (420,000)	[1]		$ (47)	47			(420,000)		(420,000)
Equity forward contract	$ 20,000				20,000					20,000
Common stock issued, net of shares withheld for employee taxes (in shares)	3,508			3,508
Common stock issued, net of shares withheld for employee taxes	$ 79,629			$ 35	(136,522)	(32,410)		248,526		79,629
Stock-based compensation	138,876				138,876					138,876
Non-controlling interest in an equity investment	1,759									0		1,759
Balance (in shares) at Oct. 31, 2018				149,265
Ending balance at Oct. 31, 2018	3,485,015			$ 1,493	1,644,830	2,543,688		(597,682)	(113,177)	3,479,152		5,863
Ending balance (Adjustment due to adoption of accounting standards related to revenue) at Oct. 31, 2018			257,594				257,594				257,594
Ending balance (Adjustment due to adoption of an accounting standard related to income taxes) at Oct. 31, 2018			$ (130,544)				$ (130,544)				$ (130,544)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	532,367					532,367				532,367
Other comprehensive income (loss), net of tax effects	$ 20,730								20,730	20,730
Purchases of treasury stock (in shares)	(2,732)			(2,732)
Purchases of treasury stock, value	$ (329,185)			$ (27)	27			(329,185)		(329,185)
Common stock issued, net of shares withheld for employee taxes (in shares)	3,798			3,798
Common stock issued, net of shares withheld for employee taxes	$ 99,103			$ 37	(163,198)	(38,961)		301,225		99,103
Stock-based compensation	153,796				153,796					153,796
Balance (in shares) at Oct. 31, 2019				150,331
Ending balance at Oct. 31, 2019	4,088,876			$ 1,503	1,635,455	3,164,144		(625,642)	(92,447)	4,083,013		5,863
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	663,447					664,347				664,347		(900)
Other comprehensive income (loss), net of tax effects	$ 38,373								38,373	38,373
Purchases of treasury stock (in shares)	(1,585)			(1,585)
Purchases of treasury stock, value	$ (242,078)			$ (14)	14			(242,078)		(242,078)
Common stock issued, net of shares withheld for employee taxes (in shares)	3,872			3,872
Common stock issued, net of shares withheld for employee taxes	$ 115,165			$ 39	(230,887)	(33,094)		379,107		115,165
Stock-based compensation	248,584				248,584					248,584
Balance (in shares) at Oct. 31, 2020				152,618
Ending balance at Oct. 31, 2020	$ 4,912,367			$ 1,528	$ 1,653,166	$ 3,795,397		$ (488,613)	$ (54,074)	$ 4,907,404		$ 4,963

[1] The first quarter of fiscal 2018 includes the settlement of the $20.0 million equity forward contract related to the September 2017 ASR.