Document And Entity Information - shares	9 Months Ended
	Dec. 31, 2018	Feb. 14, 2019
Document Information [Line Items]
Entity Registrant Name	FRIEDMAN INDUSTRIES INC
Entity Central Index Key	0000039092
Trading Symbol	frd
Current Fiscal Year End Date	--03-31
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding (in shares)		7,009,444
Document Type	10-Q
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false