Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 15, 2019	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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, 2018
Document Fiscal Year Focus	2018
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		81,934,350
Unvested at beginning of year, Number of Restricted Stock Awards (in shares)	26,500	20,500		53,700	53,000.0	102,400
Entity Public Float			$ 0.9