| Document and Entity Information | Jul. 21, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jul. 21, 2020 |
| Entity Registrant Name | HEARTLAND EXPRESS INC |
| Entity Incorporation, State or Country Code | NV |
| Entity File Number | 000-15087 |
| Entity Tax Identification Number | 93-0926999 |
| Entity Address, Address Line One | 901 NORTH KANSAS AVE |
| Entity Address, City or Town | NORTH LIBERTY |
| Entity Address, State or Province | IA |
| Entity Address, Postal Zip Code | 52317 |
| City Area Code | 319 |
| Local Phone Number | 626-3600 |
| 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 | 0000799233 |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | HTLD |
| Security Exchange Name | NASDAQ |
