Document and Entity Information (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Feb. 26, 2015	Jun. 30, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
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, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Amendment Flag	false
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		87,790,677
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	183,100	175,100		212,000	277,000	351,000
Entity Public Float			$ 959.2