Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 31, 2021
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2021
Entity File Number	0-20853
Entity Registrant Name	ANSYS, Inc.
Entity Central Index Key	0001013462
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3219960
Entity Address, Address Line One	2600 ANSYS Drive,
Entity Address, City or Town	Canonsburg,
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15317
City Area Code	844
Local Phone Number	462-6797
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		87,252,523
The Nasdaq Global Select Market
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	ANSS
Security Exchange Name	NASDAQ