| **ECONOMIC DEPENDENCY: (Details) (USD $)**                                 | 12 Months Ended |            |            | 12 Months Ended |            |             | 12 Months Ended | 1 Months Ended | 12 Months Ended |               | 0 Months Ended | 13 Months Ended |
|----------------------------------------------------------------------------|-----------------|------------|------------|-----------------|------------|-------------|-----------------|----------------|-----------------|---------------|----------------|-----------------|
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| **ECONOMIC DEPENDENCY**                                                    |            |       |       |            |       |        |            |           |            |          |           |            |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Concentration risk percentage                                              |            |       |       |            |       |        |            |           |            |          |           |            | 54.00% | 54.00% |   | 96.00% | 100.00% | 100.00% | 96.00% | 96.00% |   |   |   |   |   |
| Number of Task Orders                                                      |            |       |       |            |       |        |            | 7              |            |          |           |            |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Value of award                                                             |            |       |       |            |       |        |            |           | $ 133,000,000   | $ 145,000,000 |           | $ 145,000,000   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Term of award                                                              |            |       |       |            |       |        |            |           | 5 years         | 5 years       |           | 5 years         |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Percentage of revenue generated from Blanket Purchase Agreement            |            |       |       |            |       |        |            |           |            |          | 53.00%         |            |   |   |   |   |   |   |   |   | 53.00% |   |   |   |   |
| Percentage of revenue generated from other government contracts            |            |       |       |            |       |        |            |           |            |          |           |            |   |   | 42.00% |   |   |   |   |   |   |   |   |   |   |
| Number of Incumbent Regions                                                |            |       |       |            |       |        | 6               |           |            |          |           |            |   |   |   |   |   |   |   |   |   |   |   |   | 6 |
| Accounts receivable                                                        |            | 11,943,000 | 13,028,000 |            | 11,900,000 | 13,000,000  |            |           |            |          |           |            |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Unbilled accounts receivable                                               |            | 9,300,000  | 9,300,000  |            | 9,300,000  | 9,300,000   |            |           |            |          |           |            |   |   |   |   |   |   |   |   | 9,300,000 |   | 9,300,000 |   |   |
| Contract revenue, nonrecurring                                             | 10,800,000      |       |       | 10,800,000      |       |        |            |           |            |          |           |            |   |   |   |   |   |   |   |   |   | 10,800,000 |   |   |   |
| Unbilled accounts receivable relating to retroactive adjustments from 2008 |            |       |       |            |       | $ 9,300,000 |            |           |            |          |           |            |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Number of Option Years                                                     |            |       |       |            |       |        |            |           | 4               |          |           |            |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Length of Option                                                           |            |       |       |            |       |        |            |           | 1 year          |          |           |            |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Number of Incumbent Regions After Sucessful Bid                            |            |       |       |            |       |        |            |           |            |          |           |            |   |   |   |   |   |   |   |   |   |   |   | 7 |   |

| 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 percentage or revenue generated from services provided under the Blanket Purchase Agreement.
+ References
No definition available.
+ Details**Name:**dlhc_GovernmentContractAwardBlanketPurchaseAgreementPercentageOfRevenue**Namespace Prefix:**dlhc_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Government Contract, Length of Option to Extend Term
+ References
No definition available.
+ Details**Name:**dlhc_GovernmentContractLengthofOptiontoExtendTerm**Namespace Prefix:**dlhc_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Government Contract, Number of Incumbent Regions
+ References
No definition available.
+ Details**Name:**dlhc_GovernmentContractNumberofIncumbentRegions**Namespace Prefix:**dlhc_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Government Contract, Number of Option to Extend Term
+ References
No definition available.
+ Details**Name:**dlhc_GovernmentContractNumberofOptiontoExtendTerm**Namespace Prefix:**dlhc_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the percentage of revenue generated from other government contracts which are not currently the subject for request for proposals.
+ References
No definition available.
+ Details**Name:**dlhc_GovernmentContractOtherPercentageOfRevenue**Namespace Prefix:**dlhc_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Unbilled amounts (net of unliquidated progress payments) of government contract receivables that relate to the retroactive adjustment from 2008.
+ References
No definition available.
+ Details**Name:**dlhc_GovernmentContractReceivableUnbilledAmountsRelatingToRetroactiveAdjustments**Namespace Prefix:**dlhc_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the term of the award granted to the entity.
+ References
No definition available.
+ Details**Name:**dlhc_GovernmentContractTermofAward**Namespace Prefix:**dlhc_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of Incumbent Regions After Sucessful Bid
+ References
No definition available.
+ Details**Name:**dlhc_NumberofIncumbentRegionsAfterSucessfulBid**Namespace Prefix:**dlhc_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of Task Orders
+ References
No definition available.
+ Details**Name:**dlhc_NumberofTaskOrders**Namespace Prefix:**dlhc_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the value of the award granted to the entity.
+ References
No definition available.
+ Details**Name:**dlhc_ValueOfAward**Namespace Prefix:**dlhc_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3-4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 3 -Subparagraph a(1) -Article 5Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 4 -Article 5
+ Details**Name:**us-gaap_AccountsReceivableNetCurrent**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_ConcentrationRiskLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13537-108611Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13531-108611Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592
+ Details**Name:**us-gaap_ConcentrationRiskPercentage1**Namespace Prefix:**us-gaap_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**duration |
| 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 |