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		Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Total Synopsys Stockholders’ Equity	Non-controlling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment | Accounting Standards Update 2014-09	$ 257,594				$ 257,594	[1]			$ 257,594
Cumulative effect adjustment | Accounting Standards Update 2018-02	(130,544)				(130,544)	[2]			(130,544)
Balance (in shares) at Oct. 31, 2018			149,265
Beginning 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	271,724				271,724				271,724
Other comprehensive income (loss), net of tax effects	$ 16,457							16,457	16,457
Purchases of treasury stock (in shares)	(1,126)	[3]	(1,126)
Purchases of treasury stock, value	$ (109,185)	[3]	$ (11)	11			(109,185)		(109,185)
Equity forward contract	$ (20,000)			(20,000)					(20,000)
Common stock issued, net of shares withheld for employee taxes (in shares)	1,843	[3]	1,843
Common stock issued, net of shares withheld for employee taxes	$ 70,200		$ 18	(39,531)	(29,651)		139,364		70,200
Stock-based compensation	74,174			74,174					74,174
Balance (in shares) at Apr. 30, 2019			149,982
Ending balance at Apr. 30, 2019	3,915,435		$ 1,500	1,659,484	2,912,811		(567,503)	(96,720)	3,909,572	5,863
Balance (in shares) at Jan. 31, 2019			149,276
Beginning balance at Jan. 31, 2019	3,784,665		$ 1,493	1,654,363	2,820,910		(600,112)	(97,852)	3,778,802	5,863
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	118,210				118,210				118,210
Other comprehensive income (loss), net of tax effects	$ 1,132							1,132	1,132
Purchases of treasury stock (in shares)	(780)	[3]	(780)
Purchases of treasury stock, value	$ (80,000)	[3]	$ (8)	8			(80,000)		(80,000)
Equity forward contract	$ (20,000)			(20,000)					(20,000)
Common stock issued, net of shares withheld for employee taxes (in shares)	1,486	[3]	1,486
Common stock issued, net of shares withheld for employee taxes	$ 74,520		$ 15	(11,795)	(26,309)		112,609		74,520
Stock-based compensation	36,908			36,908					36,908
Balance (in shares) at Apr. 30, 2019			149,982
Ending balance at Apr. 30, 2019	3,915,435		$ 1,500	1,659,484	2,912,811		(567,503)	(96,720)	3,909,572	5,863
Balance (in shares) at Oct. 31, 2019			150,331
Beginning balance at Oct. 31, 2019	4,088,876	[4]	$ 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)	[5]	(1,231)
Purchases of treasury stock, value	$ (180,000)	[5]	$ (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	[5]	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)	[5]	(652)
Purchases of treasury stock, value	$ (100,000)	[5]	$ (7)	7			(100,000)		(100,000)
Equity forward contract	$ 0			0					0
Common stock issued, net of shares withheld for employee taxes (in shares)	1,358	[5]	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

[1] See Note 2. Summary of Significant Accounting Policies in the Company's Annual Report on Form 10-K for the year ended October 31, 2019 for additional information on the retained earnings adjustment due to adoption of Accounting Standards Codification (ASC) 606 and ASC 340, "Other Assets and Deferred Costs".

[2] See Note 11. Income Taxes in the Company's Annual Report on Form 10-K for the year ended October 31, 2019 for additional information on the retained earnings adjustment due to adoption of Accounting Standard Update (ASU) 2016-16.

[3] Does not include the 97,601 shares and $20.0 million equity forward contract, respectively, from the February 2019 ASR settled in May 2019.

[4] Derived from audited financial statements.

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