| Cover | Oct. 21, 2020 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Oct. 21, 2020 |
| Entity Registrant Name | ARMOUR Residential REIT, Inc. |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 001-34766 |
| Entity Tax Identification Number | 26-1908763 |
| Entity Address, Address Line One | 3001 Ocean Drive, Suite 201 |
| Entity Address, City or Town | Vero Beach, |
| Entity Address, State or Province | FL |
| Entity Address, Postal Zip Code | 32963 |
| City Area Code | 772 |
| Local Phone Number | 617-4340 |
| 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 | 0001428205 |
| Amendment Flag | false |
| Preferred Class C | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Preferred Stock, 7.00% Series C Cumulative Redeemable |
| Trading Symbol | ARR-PRC |
| Security Exchange Name | NYSE |
| Common Stock | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $0.001 par value |
| Trading Symbol | ARR |
| Security Exchange Name | NYSE |
