Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 25, 2020
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2020
Entity File Number	1-35740
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	71-0556971
Entity Address, Address Line One	3200 Industrial Park Road
Entity Address, City or Town	Van Buren
Entity Address, State or Province	AR
Entity Address, Postal Zip Code	72956
City Area Code	479
Local Phone Number	471-2500
Title of 12(b) Security	Common Stock, $0.01 Par Value
Trading Symbol	USAK
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		8,760,316
Entity Registrant Name	USA TRUCK INC.
Entity Central Index Key	0000883945
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false