Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2020	Dec. 04, 2020	Mar. 31, 2020
Document and Entity Information
Entity Registrant Name	DLH Holdings Corp.
Entity Central Index Key	0000785557
Document Type	10-K
Document Period End Date	Sep. 30, 2020
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--09-30
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Transition Report	false
Entity Common Stock, Shares Outstanding		12,531,906
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 28,949,753