Unaudited Condensed Consolidated Statements of Stockholders' Equity Statement - USD ($) shares in Thousands, $ in Thousands	Total		Common Stock	Capital in Excess of Par Value	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment [Member]	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total  Synopsys Stockholders’ Equity	Non-controlling Interest
Balance (in shares) at Oct. 31, 2019			150,331
Beginning 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	213,981				213,981				213,981
Other comprehensive income (loss), net of tax effects	$ (11,583)							(11,583)	(11,583)
Purchases of treasury stock (in shares)	(1,231)	[1]	(1,231)
Purchases of treasury stock	$ (180,000)	[1]	$ (12)	12			(180,000)		(180,000)
Equity forward contract	$ (20,000)			(20,000)					(20,000)
Common stock issued, net of shares withheld for employee taxes (in shares)	1,808	[1]	1,808
Common stock issued, net of shares withheld for employee taxes	$ 81,357		$ 18	(67,998)	(21,636)		170,973		81,357
Stock-based compensation	108,318			108,318					108,318
Balance (in shares) at Apr. 30, 2020			150,908
Ending balance at Apr. 30, 2020	4,280,949		$ 1,509	1,655,787	3,356,489		(634,669)	(104,030)	4,275,086	5,863
Balance (in shares) at Jan. 31, 2020			150,202
Beginning balance at Jan. 31, 2020	4,154,690		$ 1,502	1,626,783	3,268,205		(664,352)	(83,311)	4,148,827	5,863
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	109,920				109,920				109,920
Other comprehensive income (loss), net of tax effects	$ (20,719)							(20,719)	(20,719)
Purchases of treasury stock (in shares)	(652)	[1]	(652)
Purchases of treasury stock	$ (100,000)	[1]	$ (7)	7			(100,000)		(100,000)
Common stock issued, net of shares withheld for employee taxes (in shares)	1,358	[1]	1,358
Common stock issued, net of shares withheld for employee taxes	$ 80,623		$ 14	(27,438)	(21,636)		129,683		80,623
Stock-based compensation	56,435			56,435					56,435
Balance (in shares) at Apr. 30, 2020			150,908
Ending balance at Apr. 30, 2020	4,280,949		$ 1,509	1,655,787	3,356,489		(634,669)	(104,030)	4,275,086	5,863
Balance (in shares) at Oct. 31, 2020			152,618
Beginning 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
Beginning balance (Retained earnings adjustment due to adoption of ASC 326) at Oct. 31, 2020						$ (3,200)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	356,830				357,423				357,423	(593)
Other comprehensive income (loss), net of tax effects	$ 12,719							12,719	12,719
Purchases of treasury stock (in shares)	(1,593)		(1,593)
Purchases of treasury stock	$ (398,082)		$ (16)	16			(398,082)		(398,082)
Common stock issued, net of shares withheld for employee taxes (in shares)	1,529		1,529
Common stock issued, net of shares withheld for employee taxes	$ 48,503		$ 14	(136,749)			185,238		48,503
Stock-based compensation	163,368			163,368					163,368
Balance (in shares) at Apr. 30, 2021			152,554
Ending balance at Apr. 30, 2021	5,092,505		$ 1,526	1,679,801	4,149,620		(701,457)	(41,355)	5,088,135	4,370
Balance (in shares) at Jan. 31, 2021			152,364
Beginning balance at Jan. 31, 2021	4,886,898		$ 1,526	1,589,175	3,954,542		(628,216)	(34,775)	4,882,252	4,646
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	194,802				195,078				195,078	(276)
Other comprehensive income (loss), net of tax effects	$ (6,580)							(6,580)	(6,580)
Purchases of treasury stock (in shares)	(756)	[2]	(756)
Purchases of treasury stock	$ (195,211)	[2]	$ (8)	8			(195,211)		(195,211)
Equity forward contract	$ 50,000			50,000					50,000
Common stock issued, net of shares withheld for employee taxes (in shares)	946	[2]	946
Common stock issued, net of shares withheld for employee taxes	$ 83,010		$ 8	(38,968)			121,970		83,010
Stock-based compensation	79,586			79,586					79,586
Balance (in shares) at Apr. 30, 2021			152,554
Ending balance at Apr. 30, 2021	$ 5,092,505		$ 1,526	$ 1,679,801	$ 4,149,620		$ (701,457)	$ (41,355)	$ 5,088,135	$ 4,370

[1] Does not include the 148,953 shares and $20.0 million equity forward contract, respectively, from the February 2020 ASR settled in May 2020.

[2] Includes the 166,276 shares and $50.0 million equity forward contract, respectively, from the December 2020 ASR.