| **Significant Accounting Policies (Policies)** | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
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| **Accounting Policies [Abstract]**             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| Use of Estimates                               | Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates include valuation of goodwill, expected settlement amounts of accounts receivable, valuation allowances established against accounts receivable and deferred tax assets, measurement of loss development on workers’ compensation claims, and the valuation of derivative financial instruments associated with debt agreements. We evaluate these estimates and judgments on an ongoing basis and base our estimates on historical experience, current and expected future outcomes, third-party evaluations and various other assumptions that we believe are reasonable under the circumstances. The results of these estimates form the basis for making judgments about the carrying values of assets and liabilities as well as identifying and assessing the accounting treatment with respect to commitments and contingencies. We revise material accounting estimates if changes occur, such as more experience is acquired, additional information is obtained, or there is new information on which an estimate was or can be based. Actual results could differ from those estimates. In particular, a material reduction in the fair value of goodwill would have a material adverse effect on the Company’s financial position and results of operations. We account for the effect of a change in accounting estimate during the period in which the change occurs. |
| Revenue Recognition                            | Revenue Recognition DLH’s revenue is derived from professional and other specialized service offerings to US Government agencies through a variety of contracts, some of which are fixed-price in nature and/or sourced through Federal Supply Schedules administered by the General Services Administration (“GSA”) at fixed unit rates or hourly arrangements. We generally operate as a prime contractor, but have also entered into contracts as a subcontractor. The recognition of revenue from fixed rates is based upon objective criteria that generally do not require significant estimates that may change over time. DLH recognizes and records revenue on government contracts when it is realized, or realizable, and earned. DLH considers these requirements met when: (a) persuasive evidence of an arrangement exists; (b) the services have been delivered to the customer; (c) the sales price is fixed or determinable and free of contingencies or significant uncertainties; and (d) collectibility is reasonably assured.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Goodwill                                       | Goodwill DLH continues to review its goodwill for possible impairment or loss of value at least annually or more frequently upon the occurrence of an event or when circumstances indicate that a reporting unit’s carrying amount is greater than its fair value.  At September 30, 2015, we performed a goodwill impairment evaluation. We performed both a qualitative and quantitative assessment of factors to determine whether it was necessary to perform the goodwill impairment test. Based on the results of the work performed, the Company has concluded that no impairment loss was warranted at September 30, 2015. Factors including non-renewal of a major contract or other substantial changes in business conditions could have a material adverse effect on the valuation of goodwill in future periods and the resulting charge could be material to future periods’ results of operations. If an impairment write off of all the goodwill became necessary in future periods, a charge of up to $8.6 million would be expensed in the consolidated statement of operations. All remaining goodwill is attributable to the DLH Solutions operating subsidiary.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| Income Taxes                                   | Income Taxes DLH accounts for income taxes in accordance with the liability method, whereby deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities, using enacted tax rates in effect for the year in which the differences are expected to reverse. Deferred tax assets are reflected on the consolidated balance sheet when it is determined that it is more likely than not that the asset will be realized. This guidance also requires that deferred tax assets be reduced by a valuation allowance if it is more likely than not that some or all of the deferred tax asset will not be realized. We account for uncertain tax positions by recognizing the financial statement effects of a tax position only when, based upon the technical merits, it is "more-likely-than-not" that the position will not be sustained upon examination                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| Cash and Cash Equivalents                      | Cash and Cash EquivalentsWe consider all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. We maintain cash balances at financial institutions that are insured by the Federal Deposit Insurance Corporation (“FDIC”) up to $250,000. Deposits held with financial institutions may exceed the $250,000 limit.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |

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| - Definition
Disclosure of accounting policy for cash and cash equivalents, including the policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value.
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| - Definition
Disclosure of accounting policy for goodwill. This accounting policy also may address how an entity assesses and measures impairment of goodwill, how reporting units are determined, how goodwill is allocated to such units, and how the fair values of the reporting units are determined.
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Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.
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Disclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction.
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Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.
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