Cover - shares	6 Months Ended
	Mar. 31, 2025	May 05, 2025
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2025
Document Transition Report	false
Entity File Number	0-18492
Entity Registrant Name	DLH HOLDINGS CORP.
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	22-1899798
Entity Address, Address Line One	3565 Piedmont Road,
Entity Address, Address Line Two	Building 3,
Entity Address, Address Line Three	Suite 700
Entity Address, City or Town	Atlanta,
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30305
City Area Code	770
Local Phone Number	554-3545
Title of 12(b) Security	Common Stock
Trading Symbol	DLHC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		14,386,468
Entity Central Index Key	0000785557
Amendment Flag	false
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--09-30