Net Income per Share - Reconciliation of Weighted Average Common Shares Used to Calculate Basic Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2022	Jul. 31, 2021
Numerator:
Net income attributed to Synopsys	$ 222,626	$ 198,646	$ 831,094	$ 556,069
Denominator:
Weighted-average common shares for basic net income per share (shares)	152,938	152,635	153,082	152,619
Dilutive effect of common share equivalents (shares)	2,868	4,272	3,463	4,539
Weighted-average common shares for diluted net income per share (shares)	155,806	156,907	156,545	157,158
Net income per share attributed to Synopsys:
Basic (in USD per share)	$ 1.46	$ 1.30	$ 5.43	$ 3.64
Diluted (in USD per share)	$ 1.43	$ 1.27	$ 5.31	$ 3.54
Anti-dilutive employee stock-based awards excluded (shares)	336	355	268	405