Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2019	May 02, 2019
Document and Entity Information
Entity Registrant Name	HAYNES INTERNATIONAL INC
Entity Central Index Key	0000858655
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		12,515,480
Entity Small Business	false
Entity Emerging Growth Company	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2