Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2015	Nov. 23, 2015	Mar. 31, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	DIGI INTERNATIONAL INC.
Entity Central Index Key	0000854775
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		25,299,260
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 246,475,812