| Document and Entity Information | Dec. 01, 2021 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | PAE Inc |
| Amendment Flag | false |
| Entity Central Index Key | 0001720821 |
| Document Type | 8-K |
| Document Period End Date | Dec. 1, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38643 |
| Entity Tax Identification Number | 82-3173473 |
| Entity Address, Address Line One | 7799 Leesburg Pike |
| Entity Address, Address Line Two | Suite 300 North |
| Entity Address, City or Town | Falls Church |
| Entity Address, State or Province | VA |
| Entity Address, Postal Zip Code | 22043 |
| City Area Code | (703) |
| Local Phone Number | 717-6000 |
| Written Communications | false |
| Soliciting Material | true |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Class A [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Class A Common Stock, $0.0001 par value |
| Trading Symbol | PAE |
| Security Exchange Name | NASDAQ |
| Warrant [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Warrants |
| Trading Symbol | PAEWW |
| Security Exchange Name | NASDAQ |
