| **Business Combinations**            | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| **Business Combinations [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Business Combinations                | Business CombinationsIn accordance with Accounting Standards Codification 805, "Business Combinations" ("ASC 805") the Company records acquisitions under the purchase method of accounting, under which the acquisition purchase price is allocated to the assets acquired and liabilities assumed based upon the respective fair values.  The company utilizes estimates and in some instances, may retain the services of an independent third-party valuation firm to assist in determining the fair values of assets acquired, liabilities assumed, and contingent consideration granted.  Such estimates and valuations require the Company to make significant assumptions.  These assumption may include projections of future events and operating performance.Acquisition of Danya International, LLCOn May 3, 2016, the Company acquired 100% of the equity interests of Dayna International, LLC for a purchase price of $38.75 million. The acquisition was financed through a combination of: •borrowings of $30.0 million under the Company’s senior credit facility, •cash on hand of approximately $3.75 million, •670,242 restricted shares of DLH common stock, valued at $2.5 million based on the 20 day volume-weighted average price (VWAP) of DLH stock, or $3.73 per share, and•$2.5 million pursuant to a subordinated loan arrangement with the Company’s largest stockholder. The subordinated loan was paid off on September 30, 2016 with proceeds from an equity Rights Offering that closed on September 29, 2016. After giving effect to the issuance of the shares of common stock issued to Seller at closing, Seller beneficially owns approximately 6.5% of the Company’s outstanding shares.The acquisition of Danya International is consistent with the Company’s growth strategy, which calls for the development of new customers and service offerings both organically and through mergers and acquisitions.  The preliminary base purchase price for Danya was $38.75 million, with adjustments as necessary based on an estimated working capital excess compared to the threshold prescribed in the acquisition agreement.The estimated allocation of the purchase price is shown below, based on our assessment of the acquisition date balance sheet of Danya on May 3, 2016.  The Company is in the process of completing a third-party valuation of the acquired intangible assets.   Once the valuation is complete, we will make any adjustments as needed. Consideration paid for Danya acquisition included:(Amounts in thousands)  Cash $36,470Common stock, fair value 2,500Total Consideration $38,970(Amounts in thousands)  Net assets acquired  Cash and cash equivalents $4,009Accounts receivable 5,712Other current assets 444Total current assets 10,165Accounts payable and accrued expenses (5,013)Payroll liabilities (1,432)Net working capital surplus 3,720Property and equipment, net 403Intangible assets:  Customer relationships 7,247Covenant not to compete 1,369Other long term assets 81Net identifiable assets acquired 12,820Goodwill  26,150Net assets acquired $38,970During the twelve months ended September 30, 2016, Danya contributed approximately $16.7 million of revenue and $3.0 million income from operations.   The following table presents certain results for the twelve months ended September 30, 2016 and 2015 as though the acquisition of Danya had occurred on October 1, 2014. The unaudited pro forma information is presented for informational purposes only and is not necessarily indicative of our results if the acquisition had taken place on that date. The pro forma results presented below include amortization charges for acquired intangible assets and adjustments to interest expense incurred and exclude related acquisition expenses.  The diluted earnings per share calculation takes into account as though the acquisition took place on October 1, 2014.  The pro forma results also include the recognition of tax benefits from release of the valuation allowance of $1.8 million and $6.8 million for the twelve months ended September 30, 2016 and 2015, respectively.  See Note 13 for further discussion.  (in thousands)  Twelve Months Ended  September 30,Pro forma results 2016 2015Revenue $119,245 $114,510Net income $5,322 $9,498     Weighted shares outstanding - basic 11,347 10,954Weighted shares outstanding - diluted 12,601 11,420     Basic earnings per share $0.47 $0.87Diluted earnings per share $0.42 $0.83 |

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| - Definition
The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).
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