| Document and Entity Information Document | Nov. 01, 2019 |
| Entity Information [Line Items] | |
| Document Type | 8-K/A |
| Document Period End Date | Nov. 1, 2019 |
| Entity Registrant Name | ANSYS, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 0-20853 |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001013462 |
| Amendment Flag | true |
| Amendment Description | This Amendment No. 1 to Form 8-K (the “Amendment”) amends the Form 8-K (the “Initial 8-K”) filed on November 6, 2019 by ANSYS, Inc. (the “Company”) upon acquisition of Livermore Software Technology, LLC (“LST”). This Amendment is filed for the purpose of filing an audited statement of assets acquired and liabilities assumed on the basis of the allocation of purchase price, which has been permitted by the Securities and Exchange Commission in lieu of the financial statements and pro forma financial information required under Item 9.01(a) and 9.01(b) of Form 8-K. The financial statements and information filed within this Form 8-K/A should be read in conjunction with the Initial Form 8-K. No other changes have been made to the Initial Form 8-K. |
| 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 |
