| Document and Entity Information | Feb. 26, 2020 |
| Cover [Abstract] | |
| Entity Registrant Name | ANSYS INC |
| Amendment Flag | true |
| Entity Central Index Key | 0001013462 |
| Document Type | 8-K/A |
| Document Period End Date | Feb. 26, 2020 |
| 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 |
| Title of 12(b) Security | Common Stock, $0.01 par value per share |
| Trading Symbol | ANSS |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Amendment Description | This Current Report on Form 8-K/A (this “Amended 8-K”) is being filed for the purpose of amending and restating Item 2.02 and 9.01(d) of the Current Report on Form 8-K filed by ANSYS, Inc. on February 26, 2020 (the “Original 8-K”) to remove an incorrect reference to fiscal year 2020 and to include a correct hyperlink for Exhibit 99.2, which linked to a previous quarter’s prepared remarks in the Original 8-K. The correct hyperlink for Exhibit 99.2 is included herein under Item 9.01(d). Except as specifically stated herein, the Original 8-K remains unchanged. In accordance with Rule 12b-15 of the Securities Exchange Act of 1934, as amended, the complete text of Item 2.02. and Item 9.01(d) of the Original 8-K, as amended by this Amended 8-K, is set forth below. |
