| **Business Overview**                                                               | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
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| **Organization, Consolidation and Presentation of Financial Statements [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| Business Overview                                                                   | Business Overview DLH is a full-service provider of professional healthcare and social services to government agencies including the Department of Veteran Affairs ("VA"), Department of Health and Human Services ("HHS"), Department of Defense ("DoD"), and other government agencies. DLH Holdings Corp. (together with its subsidiaries, "DLH" or the "Company" and also referred to as "we," "us" and "our") manages its operations from its principal executive offices at 3565 Piedmont Road NE, Building 3 Suite 700, Atlanta Georgia 30305.  We employ over 1,400 skilled employees working in more than30 locations throughout the United States. On May 3, 2016, DLH acquired Danya International, LLC (“Danya”) which provides technology-enabled program management, consulting, and digital communications solutions to federal government customers. We acquired Danya to expand our ability to provide complementary business services and offerings across government markets. This acquisition is in line with our strategic growth initiatives, and we intend to continue to review and position ourselves for other potential joint venture or strategic acquisition opportunities in the future.  See Note 11 of these financial statements for further discussion.Presently, the Company derives 100% of its revenue from agencies of the Federal government, primarily as a prime contractor but also as a subcontractor to other Federal prime contractors.  A major customer is defined as a customer from whom the Company derives at least 10% of its revenues. Our largest customer continues to be the VA, which comprised approximately 72% and 95% of revenue for the twelve months ended September 30, 2016 and 2015, respectively.  Additionally, HHS represents a major customer, comprising 13% of revenue for the twelve months ended September 30, 2016  following the Danya acquisition. In addition, substantially all accounts receivable, including unbilled accounts receivable, are from agencies of the U.S. Government as of September 30, 2016  and 2015. We believe that the credit risk associated with our receivables is limited due to the creditworthiness of these customers. See Note 4, Supporting Financial Information-Accounts Receivable.As of September 30, 2016, awards from VA and HHS have anticipated periods of performance ranging from approximately one to up to four years.  These agreements are subject to the Federal Acquisition Regulations.  While there can be no assurance as to the actual amount of services that the Company will ultimately provide to VA and HHS under its current contracts, we believe that our strong working relationships and our effective service delivery support ongoing performance for the contract term.  The Company's results of operations, cash flows and financial condition would be materially adversely affected in the event that we were unable to continue our relationship with VA and HHS. |

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| - Definition
The entire disclosure for the general note to the financial statements for the reporting entity which may include, descriptions of the basis of presentation, business description, significant accounting policies, consolidations, reclassifications, new pronouncements not yet adopted and changes in accounting principles.
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