Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 06, 2021
Document Information [Line Items]
Entity Central Index Key	0000917470
Entity Registrant Name	OLYMPIC STEEL INC
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2021
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	0-23320
Entity Incorporation, State or Country Code	OH
Entity Tax Identification Number	34-1245650
Entity Address, Address Line One	22901 Millcreek Boulevard, Suite 650
Entity Address, City or Town	Highland Hills
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44122
City Area Code	216
Local Phone Number	292-3800
Title of 12(b) Security	Common stock, without par value
Trading Symbol	ZEUS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		11,077,322