Significant Accounting Policies (Policies)	12 Months Ended
Sep. 30, 2017
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 and intangible assets, valuation allowances established against accounts receivable and deferred tax assets, measurement of loss development on workers’ compensation claims, and fair value of derivatives. 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 could 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. Revenue on time and materials contracts is recognized based on hours performed times the applicable hourly rate, plus materials and other direct costs incurred on the contract. Revenue on fixed fee for service contracts is recognized over the period of performance of the contract. Revenue on cost reimbursable contracts is recognized equal to allowable costs incurred, plus a ratable portion of the applicable fee. We generally operate as a prime contractor, but have also entered into contracts as a subcontractor. Our company's current business base is 95% prime contracts and 5% subcontracts. DLH recognizes and records revenue on government contracts 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.
Business Combinations	Business Combinations In accordance with Accounting Standards Codifications 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 the liabilities assumed based upon the respective fair values. The Company utilizes some 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 considerations granted. Such estimates and valuation require the Company to make significant assumptions. These assumptions may include projections of future events and operating performance.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of the Company's cash and cash equivalents, accounts receivable, unbilled revenues, accrued expenses, accrued earn outs payable, and accounts payable approximate fair value due to the short-term nature of these instruments. The fair values of the Company's debt instruments approximate fair value because the underlying interest rates approximate market rates that the Company could obtain for similar instruments at the balance sheet dates.
Goodwill and other intangible assets	Goodwill and other intangible assets We have used the acquisition method of accounting for the May 2016 transaction, whereby the assets acquired and liabilities assumed are recognized based upon their estimated fair values at the acquisition date. The financial statements at September 30, 2016 reflected a preliminary estimate of purchase accounting, its allocation to acquired intangibles and resulting amortization.
Long Lived Assets	Long Lived Assets Equipment and improvements are stated at cost. Depreciation and amortization are provided using the straight-line method over the estimated useful asset lives (3 to 7 years) and the shorter of the initial lease term or estimated useful life for leasehold improvements. Certain costs incurred in the implementation of our Enterprise Resource Planning (ERP) system, including implementation labor, are capitalized as computer software costs. Costs incurred outside of the implementation stage are expensed as incurred. No amortization expense is recorded until the software is placed in service, after which the costs will be amortized on a straight-line basis over the estimated useful life of the software. Intangible assets are estimated at a fair value and amortized on a straight-line basis over their assessed useful lives. The assessed useful lives of the assets are 10 years.
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 be sustained upon examination.
Share-based Equity Compensation	Stock-based Equity Compensation The Company uses the fair value-based method for stock-based equity compensation. Options issued are designated as either an incentive stock or a non-statutory stock option. No option may be granted with a term of more than 10 years from the date of grant. Option awards may depend on achievement of certain performance measures determined by the Compensation Committee of our Board. Shares issued upon option exercise are newly issued common shares. All awards to employees and non-employees are recorded at fair value on the date of the grant and expensed over the period of vesting. The Company uses a binomial option pricing model to estimate the fair value of each stock option at the date of grant. Any consideration paid by the option holders to purchase shares is credited to capital stock.
Cash and Cash Equivalents	Cash and Cash Equivalents We 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.
Earnings per Share	Earnings per Share Basic earnings per share is calculated by dividing income available to common shareholders by the weighted average number of common stock outstanding and restricted stock grants that vested or are likely to vest during the period. Diluted earnings per share is calculated by dividing income available to common shareholders by the weighted average number of basic common shares outstanding, adjusted to reflect potentially dilutive securities. Diluted earnings per share is calculated using the treasury stock method.
Fair Value Measurement	The Company measures certain financial assets and liabilities at fair value on a recurring basis. The Company determines fair value based upon the exit price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants, as determined by either the principal market or the most advantageous market. Inputs used in the valuation techniques to derive fair values are classified based on a three level hierarchy. These levels are: Level 1 - Quoted prices (unadjusted) in active markets that are accessible at the measurement date for assets or liabilities. The fair value hierarchy gives the highest priority to Level 1 inputs. Level 2 - Observable prices that are based on inputs not quoted on active markets, but corroborated by market data. Observable inputs are based on market data obtained from independent sources. Level 3 - Unobservable inputs are used when little or no market data is available. The fair value hierarchy gives the lowest priority to Level 3 inputs.

Significant Accounting Policies (Policies)

12 Months Ended

Sep. 30, 2017

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 and intangible assets, valuation allowances established against accounts receivable and deferred tax assets, measurement of loss development on workers’ compensation claims, and fair value of derivatives. 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 could 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

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. Revenue on time and materials contracts is recognized based on hours performed times the applicable hourly rate, plus materials and other direct costs incurred on the contract. Revenue on fixed fee for service contracts is recognized over the period of performance of the contract. Revenue on cost reimbursable contracts is recognized equal to allowable costs incurred, plus a ratable portion of the applicable fee.

We generally operate as a prime contractor, but have also entered into contracts as a subcontractor. Our company's current business base is 95% prime contracts and 5% subcontracts. DLH recognizes and records revenue on government contracts 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.

Business Combinations

In accordance with Accounting Standards Codifications 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 the liabilities assumed based upon the respective fair values. The Company utilizes some 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 considerations granted. Such estimates and valuation require the Company to make significant assumptions. These assumptions may include projections of future events and operating performance.

Fair Value of Financial Instruments

The carrying amounts of the Company's cash and cash equivalents, accounts receivable, unbilled revenues, accrued expenses, accrued earn outs payable, and accounts payable approximate fair value due to the short-term nature of these instruments. The fair values of the Company's debt instruments approximate fair value because the underlying interest rates approximate market rates that the Company could obtain for similar instruments at the balance sheet dates.

Goodwill and other intangible assets

We have used the acquisition method of accounting for the May 2016 transaction, whereby the assets acquired and liabilities assumed are recognized based upon their estimated fair values at the acquisition date. The financial statements at September 30, 2016 reflected a preliminary estimate of purchase accounting, its allocation to acquired intangibles and resulting amortization.

Long Lived Assets

Equipment and improvements are stated at cost. Depreciation and amortization are provided using the straight-line method over the estimated useful asset lives (3 to 7 years) and the shorter of the initial lease term or estimated useful life for leasehold improvements.

Certain costs incurred in the implementation of our Enterprise Resource Planning (ERP) system, including implementation labor, are capitalized as computer software costs. Costs incurred outside of the implementation stage are expensed as incurred. No amortization expense is recorded until the software is placed in service, after which the costs will be amortized on a straight-line basis over the estimated useful life of the software.

Intangible assets are estimated at a fair value and amortized on a straight-line basis over their assessed useful lives. The assessed useful lives of the assets are 10 years.

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 be sustained upon examination.

Share-based Equity Compensation

Stock-based Equity Compensation

The Company uses the fair value-based method for stock-based equity compensation. Options issued are designated as either an incentive stock or a non-statutory stock option. No option may be granted with a term of more than 10 years from the date of grant. Option awards may depend on achievement of certain performance measures determined by the Compensation Committee of our Board. Shares issued upon option exercise are newly issued common shares. All awards to employees and non-employees are recorded at fair value on the date of the grant and expensed over the period of vesting. The Company uses a binomial option pricing model to estimate the fair value of each stock option at the date of grant. Any consideration paid by the option holders to purchase shares is credited to capital stock.

Cash and Cash Equivalents

We 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.

Earnings per Share

Basic earnings per share is calculated by dividing income available to common shareholders by the weighted average number of common stock outstanding and restricted stock grants that vested or are likely to vest during the period. Diluted earnings per share is calculated by dividing income available to common shareholders by the weighted average number of basic common shares outstanding, adjusted to reflect potentially dilutive securities. Diluted earnings per share is calculated using the treasury stock method.

Fair Value Measurement

The Company measures certain financial assets and liabilities at fair value on a recurring basis. The Company determines fair value based upon the exit price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants, as determined by either the principal market or the most advantageous market. Inputs used in the valuation techniques to derive fair values are classified based on a three level hierarchy. These levels are:

Level 1 - Quoted prices (unadjusted) in active markets that are accessible at the measurement date for assets or liabilities. The fair value hierarchy gives the highest priority to Level 1 inputs.

Level 2 - Observable prices that are based on inputs not quoted on active markets, but corroborated by market data. Observable inputs are based on market data obtained from independent sources.

Level 3 - Unobservable inputs are used when little or no market data is available. The fair value hierarchy gives the lowest priority to Level 3 inputs.