| **COMMITMENTS AND CONTINGENCIES (Details) (USD $)**                                                       | 3 Months Ended | 12 Months Ended |              |           | 3 Months Ended |
|-----------------------------------------------------------------------------------------------------------|----------------|-----------------|--------------|-----------|----------------|
||
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                          |           |            |         |      |           |   |   |
| Contract revenue, nonrecurring                                                                            |           |            | $ 10,800,000 |      |           |   |   |
| Direct costs related to nonrecurring contract revenue                                                     |           |            | 10,100,000   |      |           |   |   |
| Accounts receivable                                                                                       |           |            |         | 9,300,000 |           |   |   |
| Accrued payroll (including $8.7 million related to unbilled receivables)                                  | 10,900,000     | 11,138,000      |         | 8,700,000 |           |   |   |
| Unbilled accounts receivable                                                                              |           |            |         | 9,300,000 | 9,300,000      |   |   |
| Estimated additional indirect costs and fees associated with contract modification pending final approval |           |            |         |      |           | 400,000 | 600,000 |
| Number of subsidiaries prior to sale of assets related to PEO operation (subsidiary)                      | 17             |            |         |      |           |   |   |
| Remaining liability for penalties and interest related to payroll taxes                                   | 1,400,000      | 1,400,000       |         |      |           |   |   |
| Accrued penalties and interest related to payroll taxes                                                   | 600,000        |            |         |      |           |   |   |
| Payment of payroll taxes                                                                                  | $ 0            | $ 0             |         |      |           |   |   |

| X                                                                                                                                                                                                                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the estimated additional indirect costs and fees associated with a contract modification pending final approval.
+ References
No definition available.
+ Details**Name:**dlhc_AdditionalIndirectCostsAndFeesEstimatedAmountPendingApproval**Namespace Prefix:**dlhc_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the revenue earned during the period arising from services provided under the terms of a contract related to retroactive billings which are nonrecurring.
+ References
No definition available.
+ Details**Name:**dlhc_ContractRevenueNonrecurring**Namespace Prefix:**dlhc_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the costs incurred during the period arising from services provided under the terms of a contract related to retroactive billings which are nonrecurring.
+ References
No definition available.
+ Details**Name:**dlhc_ContractRevenueNonrecurringCost**Namespace Prefix:**dlhc_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the remaining liability for penalties and interest related to payroll taxes.
+ References
No definition available.
+ Details**Name:**dlhc_LossContingencyPayrollTaxesPenaltiesAndInterestAccrued**Namespace Prefix:**dlhc_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the penalties and interest sought by IRS related to payroll taxes.
+ References
No definition available.
+ Details**Name:**dlhc_LossContingencyPayrollTaxesPenaltiesAndInterestSought**Namespace Prefix:**dlhc_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the number of subsidiaries of the entity prior to the sale of the assets from discontinued operation in fiscal 2003.
+ References
No definition available.
+ Details**Name:**dlhc_NumberOfSubsidiariesOperatingBeforeSaleOfAssetsOfDiscontinuedOperationInFiscal2003**Namespace Prefix:**dlhc_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the amount of statutory payroll taxes paid through that date.
+ References
No definition available.
+ Details**Name:**dlhc_PaymentOfPayrollTaxes**Namespace Prefix:**dlhc_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_AccountsNotesAndLoansReceivableLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20 -Article 5Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.20) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
+ Details**Name:**us-gaap_EmployeeRelatedLiabilitiesCurrent**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of receivables that are derived from government contracts.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 912 -SubTopic 310 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6471842&loc=d3e55295-109406
+ Details**Name:**us-gaap_GovernmentContractReceivable**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Unbilled amounts (net of unliquidated progress payments) of government contract receivables.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 912 -SubTopic 310 -Section 45 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=6471842&loc=d3e55376-109406
+ Details**Name:**us-gaap_GovernmentContractReceivableUnbilledAmounts**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |