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		6 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2022	Apr. 30, 2021
Numerator:
Net income attributed to Synopsys	$ 294,781	$ 195,078	$ 608,468	$ 357,423
Denominator:
Weighted-average common shares for basic net income per share (shares)	153,090	152,725	153,154	152,612
Dilutive effect of common share equivalents (shares)	3,077	4,352	3,661	4,614
Weighted-average common shares for diluted net income per share (shares)	156,167	157,077	156,815	157,226
Net income per share attributed to Synopsys:
Basic (in USD per share)	$ 1.93	$ 1.28	$ 3.97	$ 2.34
Diluted (in USD per share)	$ 1.89	$ 1.24	$ 3.88	$ 2.27
Anti-dilutive employee stock-based awards excluded (shares)	1,259	466	986	415