| **Employee Benefit Plans (Details) - USD ($) $ in Thousands**             | 12 Months Ended |
|---------------------------------------------------------------------------|-----------------|
||
| **Compensation and Retirement Disclosure [Abstract]**                     |            |   |
| Defined Contribution Plan, Cost Recognized                                | $ 24            | $ 5 |
| Defined Contribution Plan Employers Matching, Contribution Vesting Period | 4 years         |   |

| X                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the vesting period during which the employer contributes a matching contribution to the defined contribution plan.
+ References
No definition available.
+ Details**Name:**dlhc_DefinedContributionPlanEmployersMatchingContributionVestingPeriod**Namespace Prefix:**dlhc_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
+ Details**Name:**us-gaap_CompensationAndRetirementDisclosureAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of the cost recognized during the period for defined contribution plans.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942
+ Details**Name:**us-gaap_DefinedContributionPlanCostRecognized**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |