Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2020	Feb. 15, 2021	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Document Information [Line Items]
Entity Registrant Name	HEARTLAND EXPRESS, INC.
Entity Central Index Key	0000799233
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Current Reporting Status	Yes
Amendment Flag	false
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		79,977,102
Unvested, Number of Restricted Stock Awards (in shares)	59,700	53,700		52,150	26,500	53,700
Entity Public Float			$ 0.9
City Area Code	319
Local Phone Number	626-3600
Entity Incorporation, State or Country Code	NV
Entity File Number	0-15087
Entity Address, Address Line One	901 Heartland Way
Entity Address, City or Town	North Liberty
Entity Address, State or Province	IA
Security Exchange Name	NASDAQ
Entity Address, Postal Zip Code	52317
Entity Tax Identification Number	93-0926999
Document Transition Report	false
Entity Interactive Data Current	Yes
Trading Symbol	HTLD
Document Annual Report	true
Title of 12(g) Security	Common Stock, $0.01 par value
ICFR Auditor Attestation Flag	true