Alion - IPS S-1/A 6 May 14 IPO registration (amended) Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Dec. 31, 2013
Document And Entity Information [Abstract]	'
Document Type	'S-1/A
Amendment Flag	'true
Amendment Description	'Amendment no. 3
Document Period End Date	31-Dec-13
Document Fiscal Year Focus	'2014
Entity Registrant Name	'ALION SCIENCE & TECHNOLOGY CORP
Entity Central Index Key	'0001166568
Entity Filer Category	'Non-accelerated Filer
Effective Amendment Number	'3

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Sep. 30, 2010
In Thousands, unless otherwise specified
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	$4,687	$25,613	'	'	$19,461	$27,227	'	'	'	$20,818	$26,695
Accounts receivable, net	168,963	172,604	'	'	'	175,293	'	'	'	'	'
Receivable due from ESOP Trust	'	930	'	'	'	1,129	'	'	'	'	'
Prepaid expenses and other current assets	5,648	4,483	'	'	'	5,448	'	'	'	'	'
Total current assets	179,298	203,630	211,464	223,550	203,722	209,097	211,266	200,703	205,819	'	'
Property, plant and equipment, net	9,070	9,668	'	'	'	10,605	'	'	'	'	'
Intangible assets, net	1,735	2,040	'	'	'	5,242	'	'	'	'	'
Goodwill	398,921	398,921	'	'	'	398,921	'	'	'	'	'
Other assets	10,368	10,367	'	'	'	11,431	'	'	'	'	'
Total assets	599,392	624,626	'	'	'	635,296	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Interest payable	15,590	17,758	'	'	'	17,658	'	'	'	'	'
Secured Notes	326,313	'	'	'	'	'	'	'	'	'	'
Trade accounts payable	59,536	61,622	'	'	'	44,793	'	'	'	'	'
Accrued liabilities	36,909	39,393	'	'	'	52,460	'	'	'	'	'
Accrued payroll and related liabilities	31,733	37,954	'	'	'	39,926	'	'	'	'	'
Billings in excess of revenue earned	4,562	4,334	'	'	'	2,666	'	'	'	'	'
Total current liabilities	474,643	161,061	167,253	171,700	157,168	157,503	166,520	152,200	166,226	'	'
Secured Notes	'	322,286	'	'	'	306,502	'	'	'	'	'
Unsecured Notes	234,038	233,832	'	'	'	242,923	'	'	'	'	'
Accrued compensation and benefits, excluding current portion	5,998	5,736	'	'	'	5,905	'	'	'	'	'
Non-current portion of lease obligations	12,540	12,821	'	'	'	12,364	'	'	'	'	'
Deferred income taxes	59,873	58,130	'	'	'	51,156	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Redeemable common stock, $0.01 par value, 20,000,000 shares authorized; 7,641,493 shares issued and outstanding at December 31, 2013; 7,641,391 shares issued and outstanding at September 30, 2013	61,896	61,895	'	'	'	110,740	'	'	'	'	'
Common stock warrants	20,785	20,785	'	'	'	20,785	'	'	'	'	'
Accumulated other comprehensive loss	130	130	'	'	'	-149	'	'	'	'	'
Accumulated deficit	-270,511	-252,050	'	'	'	-272,433	'	'	'	'	'
Total liabilities, redeemable common stock and accumulated deficit	$599,392	$624,626	'	'	'	'	'	'	'	'	'

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Statement Of Financial Position [Abstract]	'	'	'
Redeemable common stock, par value	$0.01	$0.01	$0.01
Redeemable common stock, shares authorized	20,000,000	20,000,000	8,000,000
Redeemable common stock, shares issued	7,641,493	7,641,391	6,731,889
Redeemable common stock, shares outstanding	7,641,493	7,641,391	6,731,889

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations and Comprehensive Loss (USD $)

3 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Income Statement [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

$185,380

'

'

'

$204,329

'

'

'

'

$848,972

$817,204

$787,314

Direct contract expense

145,275

'

'

'

160,635

'

'

'

'

669,504

632,831

603,481

Gross profit

40,105

42,822

46,633

46,319

43,694

47,673

46,472

46,681

43,547

179,468

184,373

183,833

Operating expenses

18,864

'

'

'

22,250

'

'

'

'

84,128

91,494

83,035

General and administrative

18,993

'

'

'

11,804

'

'

'

'

53,139

52,441

65,305

Operating income

2,248

'

'

'

9,640

'

'

'

'

42,201

40,438

35,493

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Interest income

11

'

'

'

17

'

'

'

'

55

78

45

Interest expense

-18,948

'

'

'

-18,919

'

'

'

'

-75,700

-74,934

-73,919

Other

-28

'

'

'

-15

'

'

'

'

-84

-55

32

Total other (expense) income

-18,965

'

'

'

-18,917

'

'

'

'

-71,816

-74,911

-72,903

Loss before taxes

-16,717

'

'

'

-9,277

'

'

'

'

-29,615

-34,473

-37,410

Income tax expense

-1,745

'

'

'

-1,744

'

'

'

'

-6,977

-6,974

-6,974

Net loss

-18,462

-9,353

-7,087

-9,131

-11,021

-9,526

-8,866

-10,245

-12,810

-36,592

-41,447

-44,384

Basic and diluted loss per share

($2.41)

'

'

'

($1.64)

'

'

'

'

($5.39)

($6.74)

($7.83)

Basic and weighted average common shares outstanding

7,659,817

'

'

'

6,726,417

'

'

'

'

6,787,660

6,148,438

5,671,977

Net loss

-18,462

-9,353

-7,087

-9,131

-11,021

-9,526

-8,866

-10,245

-12,810

-36,592

-41,447

-44,384

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Postretirement actuarial gains

'

'

'

'

'

'

'

'

'

279

26

55

Comprehensive loss

($18,462)

'

'

'

($11,021)

'

'

'

'

($36,313)

($41,421)

($44,329)

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:	'	'
Net loss	($18,462)	($11,021)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation and amortization	1,307	2,491
Bad debt expense	250	'
Paid-in-kind interest	1,660	1,626
Amortization of debt issuance costs	2,694	2,656
Incentive and stock-based compensation	805	752
Deferred income taxes	1,744	1,744
Other gains	90	4
Changes in assets and liabilities:	'	'
Accounts receivable	3,391	-3,166
Other assets	-759	-189
Trade accounts payable	-2,085	15,087
Accrued liabilities	-8,317	-15,063
Interest payable	-2,168	-1,545
Other liabilities	-53	307
Net cash used in operating activities	-19,903	-6,317
Cash flows from investing activities:	'	'
Capital expenditures	-273	-603
Net cash used in investing activities	-273	-603
Cash flows from financing activities:	'	'
Payment of debt issue costs	-750	'
Revolver borrowings	10,000	'
Revolver repayments	-10,000	'
Redeemable common stock purchased from ESOP Trust	-934	-1,975
Redeemable common stock sold to ESOP Trust	934	1,129
Net cash used in financing activities	-750	-846
Net decrease in cash and cash equivalents	-20,926	-7,766
Cash and cash equivalents at beginning of period	25,613	27,227
Cash and cash equivalents at end of period	4,687	19,461
Supplemental disclosure of cash flow information:	'	'
Cash paid for interest	16,746	16,164
Cash paid for taxes	'	'
Non-cash investing and financing activities:	'	'
Paid-in-kind notes issued	$3,298	$3,234

Description_and_Formation_of_t

Description and Formation of the Business	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Accounting Policies [Abstract]	'	'
Description and Formation of the Business	'	'
	(1) Description and Formation of the Business	(1) Description and Formation of the Business
	Alion Science and Technology Corporation and its subsidiaries (collectively, the Company, Alion or we) provide advanced engineering, information technology, naval architecture and operational solutions to strengthen national security and drive business results. For customers in defense, civilian government, foreign governments and commercial industries worldwide, Alion’s engineered solutions support smarter decision-making and enhanced readiness in rapidly-changing environments.	Alion Science and Technology Corporation and its subsidiaries (collectively, the Company, Alion or we) provide advanced engineering, information technology, naval architecture and operational solutions to strengthen national security and drive business results. For customers in defense, civilian government, foreign governments and commercial industries worldwide, Alion’s engineered solutions support smarter decision-making and enhanced readiness in rapidly-changing environments.
	Alion was formed as a for-profit S-Corporation in October 2001, to purchase substantially all of the assets and certain liabilities of IIT Research Institute (IITRI), a not-for-profit corporation controlled by the Illinois Institute of Technology (IIT). In December 2002, Alion acquired substantially all of IITRI’s assets and liabilities except its Life Sciences Operation, for $127.3 million. Prior to that, the Company’s activities were organizational in nature. In 2010, the Company became a C corporation when it ceased to qualify as an S corporation.	Alion was formed as a for-profit S-Corporation in October 2001, to purchase substantially all of the assets and certain liabilities of IIT Research Institute (IITRI), a not-for-profit corporation controlled by the Illinois Institute of Technology (IIT). In December 2002, Alion acquired substantially all of IITRI’s assets and liabilities except its Life Sciences Operation, for $127.3 million. Prior to that, the Company’s activities were organizational in nature. In 2010, the Company became a C corporation when it ceased to qualify as an S corporation.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Accounting Policies [Abstract]	'		'
Summary of Significant Accounting Policies	'		'
	-2	Summary of Significant Accounting Policies	(2) Summary of Significant Accounting Policies
	Basis of Presentation and Principles of Consolidation		Basis of Presentation and Principles of Consolidation
	The accompanying unaudited condensed consolidated financial statements include the accounts of Alion Science and Technology Corporation (a Delaware corporation), and its wholly-owned subsidiaries and have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission. Certain information and note disclosures normally included in the annual financial statements, prepared in accordance with generally accepted accounting principles in the United States of America (GAAP), have been omitted pursuant to those rules and regulations. However, the Company believes that the disclosures made are adequate to make the information presented not misleading. The statements are prepared on the accrual basis of accounting and include the accounts of Alion and its wholly-owned subsidiaries from their date of acquisition or formation. All inter-company accounts have been eliminated in consolidation. There have been no changes to Alion’s subsidiaries in the current fiscal year.		The accompanying audited consolidated financial statements include the accounts of Alion Science and Technology Corporation (a Delaware corporation) and its wholly-owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles on the accrual basis of accounting. The statements include the accounts of Alion and its wholly-owned subsidiaries from date of formation or acquisition. All inter-company accounts have been eliminated in consolidation. The wholly-owned subsidiaries are:
	In management’s opinion, the accompanying unaudited condensed consolidated financial statements reflect all adjustments consisting of normal recurring adjustments and reclassifications that are necessary for fair presentation of the periods presented. The results for the three months ended December 31, 2013 are not necessarily indicative of the results to be expected for the full fiscal year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s latest annual report on Form 10-K for the year ended September 30, 2013.
	Going Concern Assumption			•	Innovative Technology Solutions Corporation (ITSC) – acquired October 2003
	The accompanying financial statements are prepared on the going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Alion has a history of losses that has resulted, in part, in the Company not having the means to repay the principal associated with our Secured and Unsecured Notes as they come due on November 1, 2014 and February 1, 2015, respectively. In the first quarter of fiscal 2014, our Secured Notes were reclassified to current liabilities based on their November 1, 2014 maturity. Our Unsecured Notes will be reclassified to current liabilities in the second quarter of fiscal 2014.
	Our liabilities exceed our assets which makes refinancing our debt more difficult and expensive. Operating cash flow is insufficient to repay the Secured and Unsecured Notes at maturity, which raises substantial doubt as to the Company’s ability to continue as a going concern.			•	Alion - IPS Corporation (IPS) – acquired February 2004
	Management’s current forecasts of future results could differ materially due to general economic uncertainties, sequestration’s effect on government spending levels in the coming fiscal year, collections delays from the October 2013 government shutdown and risks associated with future federal government procurement and contracting actions. Management’s cash flow projections indicate that absent a refinancing transaction or series of transactions, the Company will be unable to pay the principal and accumulated unpaid interest on its Secured and Unsecured Notes when those instruments come due in November 2014 and February 2015.
	Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of receiving an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this financial covenant. The Company paid no fee for this waiver.			•	Alion - METI Corporation (METI) – acquired February 2005
	Alion depends heavily on federal government prime contracts and subcontracts which account for nearly all the Company’s revenue. Interruptions in the government funding process, whether from federal budget delays, debt ceiling limitations, government shutdowns, sequestration or Department of Defense spending cuts could materially adversely affect the Company’s revenue and cash flows for the coming fiscal year and beyond. This could cause Alion to be unable to fund operations, meet debt service requirements or comply with the Credit Agreement’s Consolidated EBITDA covenant.			•	Alion - CATI Corporation (CATI) – acquired February 2005
	If Alion were unable to meet the Credit Agreement Consolidated EBITDA covenant, the Company would be unable to borrow funds under the revolving credit facility which would remove a source of liquidity for the Company. Alion could be required to immediately repay any amount then outstanding under the Credit Agreement. The Company could seek an additional covenant waiver or an amendment to the Credit Agreement in order to preserve its ability to borrow funds as and when needed. The Credit Agreement expires on August 22, 2014. Management can provide no assurance that Alion would be able to obtain an amendment or waiver, or if one were available, that the terms would be favorable. If the Company were unable to obtain a requested waiver or amendment, it might be unable to pay its debts as they became due. In each of the past three fiscal years, Alion generated sufficient cash flow from operations to fulfill its financial commitments, including debt service.
	Management is actively engaged in efforts to refinance, retire or amend Alion’s existing debt agreements. On December 24, 2013, we executed a Refinancing Support Agreement with the holders of a majority of our outstanding Unsecured Notes regarding potential transactions to refinance our outstanding indebtedness. Management can provide no assurance that Alion will be able to conclude a refinancing of its Unsecured Notes or that additional financing will be available to retire or replace the Secured Notes, and if available, that terms of any transaction would be favorable.			•	Alion International Corporation (Alion International) – established February 2005
	On the basis of these risks and uncertainties, management has determined that there is substantial doubt about the Company’s ability to continue as a going concern. Alion’s unaudited condensed consolidated financial statements do not include any adjustments to reflect the possible effects on the recoverability of assets or the amounts of liabilities that may result from resolving uncertainties about the Company’s ability to continue as a going concern.
	Fiscal, Quarter and Interim Periods			•	Alion Science and Technology (Canada) Corporation – established February 2005
	Alion’s fiscal year ends on September 30. The Company operates based on a three-month quarter, four-quarter fiscal year with quarters ending December 31, March 31, June 30, and September 30.
	Use of Estimates			•	Alion - JJMA Corporation (JJMA) – acquired April 2005
	Preparing financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect amounts reported for assets and liabilities, disclosures of contingent assets and liabilities as of financial statement dates and amounts reported for operating results for each period presented. Actual results are likely to differ from those estimates, but management does not believe such differences will materially affect Alion’s financial position, results of operations, or cash flows.
	Revenue Recognition			•	Alion - BMH Corporation (BMH) – acquired February 2006
	Alion derives its revenue from delivering technology services under three types of contracts. Some contracts provide for reimbursement of costs plus fees; others are fixed-price or time-and-material type contracts. We recognize revenue when a contract has been executed, the contract price is fixed or determinable, delivery of services or products has occurred, and our ability to collect the contract price is considered reasonably assured. Alion applies the percentage-of-completion method in Accounting Standards Codification (ASC) 605 – Revenue Recognition to recognize revenue.
	Alion recognizes revenue on cost-reimbursement contracts as it incurs costs and includes estimated fees earned. The Company recognizes time-and-material contract revenue at negotiated, fixed, contractually billable rates as it delivers labor hours and incurs other direct expenses. We use various performance measures under the percentage-of-completion method to recognize revenue for fixed-price contracts. Estimating contract costs at completion and recognizing revenue appropriately involve significant management estimates. Actual costs may differ from estimated costs and affect estimated profitability and revenue recognition timing. From time to time, facts develop that require us to revise estimated total costs or expected revenue. We record the cumulative effect of revised estimates in the period when the facts requiring revised estimates become known. We recognize the full amount of anticipated losses on any contract in the period a loss becomes known. For each of the periods presented, the cumulative effects of revised estimates were immaterial to the Company’s financial performance.			•	Washington Consulting, Inc. (WCI) – acquired February 2006
	U.S. federal government contracts are subject to periodic funding by our contracting agency customers. A customer may fund a contract at inception or incrementally throughout the period of performance as services are provided. If we determine contract funding is not probable, we defer revenue recognition until realization is probable. The federal government can audit Alion’s contract costs and adjust amounts through negotiation. The federal government considers Alion a major contractor and maintains an office on site. The Defense Contract Audit Agency (DCAA) is currently auditing our 2007 claimed indirect costs. We are negotiating our 2006 indirect rates and have settled our rates through 2005. We timely submitted our indirect cost proposals for all open fiscal years. We have recorded revenue on federal government contracts in amounts we expect to realize.
	We recognize revenue on unpriced change orders as we incur expenses and only to the extent it is probable we will recover such costs. The Company recognizes revenue in excess of costs on unpriced change orders only when management can also estimate beyond a reasonable doubt the amount of excess and experience provides a sufficient basis for recognition. Alion recognizes revenue on claims as expenses are incurred and only to the extent it is probable we will recover such costs and can reliably estimate the amount we will recover.			•	Alion—MA&D Corporation (MA&D) – acquired May 2006
	Income Taxes
	Alion accounts for income taxes by applying the provisions in currently enacted tax laws. We determine deferred income taxes based on the estimated future tax effects of differences between the financial statement and tax bases of our assets and liabilities. Deferred income tax provisions and benefits change as assets or liabilities change from year to year. In providing for deferred taxes, Alion considers the tax regulations of the jurisdictions where we operate; estimated future taxable income; and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies change, the carrying value of deferred tax assets and liabilities may require adjustment.			•	Alion Offshore Services, Inc. (Alion Offshore) – established May 2006
	Alion has a history of operating losses for both tax and financial statement purposes. The Company has recorded valuation allowances equal to deferred tax assets based on the likelihood that we may not be able to realize the value of these assets. Alion recognizes the benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain our position following an audit. For tax positions meeting the “more likely than not” threshold, we recognize the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
	Cash and Cash Equivalents			•	Washington Consulting Government Services, Inc. (WCGS) – established July 2007
	The Company considers cash in banks, and deposits with financial institutions with maturities of three months or less at time of purchase which it can liquidate without prior notice or penalty, to be cash and cash equivalents.
	Accounts Receivable and Billings in Excess of Revenue Earned			•	Alion Asia Corporation (Alion Asia) – established May 2012
	Accounts receivable include billed accounts receivable and unbilled receivables. Unbilled receivables consist of costs and fees which are billable upon occurrence of a specific event, amounts billable after the balance sheet date and revenue in excess of billings on uncompleted contracts (accumulated project expenses and fees which were not billed or were not currently billable as of the date of the consolidated balance sheet). Unbilled accounts receivable include revenue recognized for customer-requested work Alion performed on new and existing contracts for which the Company had not received contracts or contract modifications. Accounts receivable are stated as estimated realized value. The allowance for doubtful accounts is Alion’s best estimate of the amount of probable losses in the Company’s existing billed and unbilled accounts receivable. The Company determines the allowance using specific identification and historical write-off experience based on receivable age. Billings in excess of revenue and advance collections from customers represent amounts received from or billed to customers in excess of project revenue recognized to date.
	Property, Plant and Equipment			•	Alion Maritime India Private Limited (Alion India) – established May 2013
	Leasehold improvements, software and equipment are recorded at cost. Maintenance and repairs that do not add significant value or significantly lengthen an asset’s useful life are charged to current operations. Software and equipment are depreciated on the straight-line method over their estimated useful lives (typically 3 years for software and 5 years for equipment). Leasehold improvements are amortized on the straight-line method over the shorter of the asset’s estimated useful life or the life of the lease. Upon sale or retirement of an asset, costs and related accumulated depreciation are deducted from the accounts, and any gain or loss is recognized in the unaudited condensed consolidated statements of operations.		Fiscal, Quarter and Interim Periods
	Goodwill		Alion’s fiscal year ends on September 30. The Company operates based on a three-month quarter, four-quarter fiscal year with quarters ending December 31, March 31, June 30, and September 30.
	Alion assigns the purchase price paid to acquire the stock or assets of a business to the net assets acquired based on the estimated fair value of assets acquired and liabilities assumed. Goodwill is the purchase price in excess of the estimated fair value of the tangible net assets and separately identified intangible assets acquired. There have been no changes to goodwill carrying value this year.		Use of Estimates
	The Company accounts for goodwill and other intangible assets in accordance with the provisions of ASC 350 – Intangibles-Goodwill and Other. Alion operates in one segment and tests goodwill at the reporting unit level. There are two reporting units. We review goodwill for impairment in the fourth quarter each year, and whenever events or circumstances indicate goodwill might be impaired. We are required to recognize an impairment loss to the extent our goodwill carrying value at the reporting unit level exceeds fair value. Evaluating goodwill involves significant management estimates. To date, our annual reviews have resulted in no goodwill impairment adjustments. See Note 8 for a detailed discussion of the Company’s goodwill impairment testing process.		Preparing financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect amounts reported for assets and liabilities, disclosures of contingent assets and liabilities as of financial statement dates and amounts reported for operating results for each period presented. Actual results are likely to differ from those estimates, but management does not believe such differences will materially affect Alion’s financial position, results of operations, or cash flows.
	Intangible Assets
	Alion amortizes intangible assets as it consumes economic benefits over estimated useful lives. As of December 31, 2013, the Company had approximately $1.7 million in net intangible assets, including contracts purchased in the JJMA acquisition and purchased software licenses. The JJMA contract portfolio has a remaining useful life of approximately 1.5 years.		Summary of Critical Accounting Policies
	Redeemable Common Stock		Going Concern Assumption
	There is no public market for Alion’s redeemable common stock and therefore no observable price for its equity, individually or in the aggregate. The Employee Stock Ownership Plan (ESOP) Trust holds all the Company’s outstanding common stock. Under certain circumstances, ESOP beneficiaries can require the ESOP Trust to distribute the value of their beneficial interests. The Internal Revenue Code (IRC) and the Employee Retirement Income Security Act (ERISA) require the Company to offer ESOP participants who receive Alion common stock a liquidity put right. The put right requires the Company to purchase distributed shares at their then- current fair market value at any time during two put option periods. Common stock distributed by the ESOP Trust is subject to a right of first refusal. Prior to any subsequent transfer, shares must first be offered to the Company and then to the ESOP Trust. Eventual redemption of shares of Alion common stock as a result of distributions is outside the Company’s control. Therefore, Alion classifies its outstanding shares of redeemable common stock as other than permanent equity.		The accompanying financial statements are prepared on the going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Alion has a history of losses that has resulted, in part, in the Company not having the means to repay the principal associated with our Secured and Unsecured Notes as they come due on November 1, 2014 and February 1, 2015, respectively. Further, liabilities in excess of our assets makes refinancing our debt more difficult and expensive, and an insufficient level of cash flow from operating activities to repay the Secured and Unsecured Notes at maturity, raises substantial doubt as to the Company’s ability to continue as a going concern.
	At each reporting date, Alion is required to increase or decrease the reported value of its outstanding common stock to reflect its estimated redemption value. Management estimates the value of Alion’s obligation to repurchase its outstanding shares of redeemable common stock by considering, in part, the most recent price at which the Company was able to sell shares to the ESOP Trust. The reported value of outstanding redeemable common stock equals the current share price multiplied by total shares issued and outstanding.		Management’s current forecasts of future results could differ materially due to general economic uncertainties, sequestration’s effect on government spending levels in the coming fiscal year, collections delays from the October 2013 government shutdown and risks associated with future federal government procurement and contracting actions. Management’s cash flow projections indicate that absent a refinancing transaction or series of transactions, the Company will be unable to pay the principal and accumulated unpaid interest on its Secured and Unsecured Notes when those instruments come due in November 2014 and February 2015.
	In its fiduciary capacity, the ESOP Trustee is independent of the Company and its management. Consistent with its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the ESOP Trustee may acquire or dispose of investments in Alion common stock. The Audit and Finance Committee of Alion’s Board of Directors reviews the reasonableness of the amount management has determined Alion should recognize for the Company’s obligation to repurchase shares of its outstanding redeemable common stock. The Audit and Finance Committee considers various factors in its review, including, in part, the most recent valuation report prepared for, and the share price selected by the ESOP Trustee.		Alion depends heavily on federal government prime contracts and subcontracts which account for nearly all the Company’s revenue. Interruptions in the government funding process, whether from federal budget delays, debt ceiling limitations, government shutdowns, sequestration or Department of Defense spending cuts could materially adversely affect the Company’s revenue and cash flows for the coming fiscal year and beyond. This could cause Alion to be unable to fund operations, meet debt service requirements or comply with the Credit Agreement’s Consolidated EBITDA covenant.
	Alion records changes in the reported value of its outstanding common stock through an offsetting charge or credit to accumulated deficit. The Company recognizes changes in the fair value of its redeemable common stock on March 31 and September 30 each year. The accumulated deficit at December 31, 2013, included a $67.5 million cumulative benefit for changes in share price which reduced the Company’s aggregate share redemption obligation. Outstanding redeemable common stock had an aggregate fair value of approximately $61.9 million as of December 31, 2013.		Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of receiving an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this financial covenant. The Company paid no fee for this waiver
			If Alion were unable to meet the Credit Agreement Consolidated EBITDA covenant, the Company would be unable to borrow funds under the revolving credit facility which would remove a source of liquidity for the Company. Alion could be required to immediately repay any amount then outstanding under the Credit Agreement. The Company could seek an additional covenant waiver or an amendment to the Credit Agreement in order to preserve its ability to borrow funds as and when needed. The Credit Agreement expires on August 22, 2014. Management can provide no assurance that Alion would be able to obtain an amendment or waiver, or if one were available, that the terms would be favorable. If the Company were unable to obtain a requested waiver or amendment, it might be unable to pay its debts as they became due. In each of the past three fiscal years, Alion generated sufficient cash flow from operations to fulfill its financial commitments, including debt service.
	Concentration of Credit Risk		Management is actively engaged in identifying additional potential sources of cash to refinance, retire or amend Alion’s existing debt agreements. We have reached a preliminary understanding with the holders of a majority of our outstanding Unsecured Notes regarding potential refinancing transactions involving our outstanding indebtedness and are negotiating a definitive agreement. However, Management can provide no assurance that Alion will be able to conclude a refinancing of its Unsecured Notes or that additional financing will be available to retire or replace its Secured Notes, and if available, that terms of any transaction would be favorable.
	Alion is subject to credit risk for its cash equivalents and accounts receivable. The Company believes the high credit quality of its cash equivalent investments limits its credit risk with respect to such investments. Alion believes its concentration of credit risk with respect to accounts receivable is limited as the receivables are principally due from the federal government. Approximately 21% of the Company’s receivables are due from commercial customers including other prime contractors.		On the basis of these risks and uncertainties, management has determined that there is substantial doubt about the Company’s ability to continue as a going concern. Alion’s audited consolidated financial statements do not include any adjustments to reflect the possible effects on the recoverability of assets or the amounts of liabilities that may result from resolving uncertainties about the Company’s ability to continue as a going concern.
	Fair Value of Financial Instruments		Revenue Recognition
	Alion is required to disclose the fair value of its financial instruments but is not required to record its senior long-term debt at fair value. See Note 10 for a discussion of Alion’s current and long-term debt and Note 11 for the related fair value disclosures. The fair value of cash, cash equivalents, accounts payable and accounts receivable does not differ materially from carrying value because of the short maturity of those instruments.		Alion derives its revenue from delivering technology services under three types of contracts. Some contracts provide for reimbursement of costs plus fees; others are fixed-price or time-and-material type contracts. We recognize revenue when a contract has been executed, the contract price is fixed or determinable, delivery of services or products has occurred, and our ability to collect the contract price is considered reasonably assured. Alion applies the percentage-of-completion method in Accounting Standards Codification (ASC) 605 – Revenue Recognition to recognize revenue.
	Off-Balance Sheet Financing Arrangements
	Alion accounts for operating leases entered into in the routine course of business in accordance with ASC 840 – Leases. We have no off-balance sheet financing arrangements other than operating leases and letters of credit under our revolving credit facility. Alion has no relationship with any unconsolidated or special purpose entity and has not issued any associated guarantees.		Alion recognizes revenue on cost-reimbursement contracts as it incurs costs and includes estimated fees earned. The Company recognizes time-and-material contract revenue at negotiated, fixed, contractually billable rates as it delivers labor hours and incurs other direct expenses. We use various performance measures under the percentage-of-completion method to recognize revenue for fixed-price contracts. Estimating contract costs at completion and recognizing revenue appropriately involve significant management estimates. Actual costs may differ from estimated costs and affect estimated profitability and revenue recognition timing. From time to time, facts develop that require us to revise estimated total costs or expected revenue. We record the cumulative effect of revised estimates in the period when the facts requiring revised estimates become known. We recognize the full amount of anticipated losses on any contract in the period a loss becomes known. For each of the periods presented, the cumulative effects of revised estimates were immaterial to the Company’s financial performance.
			U.S. federal government contracts are subject to periodic funding by our contracting agency customers. A customer may fund a contract at inception or incrementally throughout the period of performance as services are provided. If we determine contract funding is not probable, we defer revenue recognition until realization is probable. The federal government can audit Alion’s contract costs and adjust amounts through negotiation. The federal government considers Alion a major contractor and maintains an office on site. The Defense Contract Audit Agency (DCAA) is currently auditing our 2007 claimed indirect costs. We are negotiating our 2006 indirect rates and have settled our rates through 2005. We timely submitted our indirect cost proposals for all open fiscal years. We have recorded revenue on federal government contracts in amounts we expect to realize.
			We recognize revenue on unpriced change orders as we incur expenses and only to the extent it is probable we will recover such costs. The Company recognizes revenue in excess of costs on unpriced change orders only when management can also estimate beyond a reasonable doubt the amount of excess and experience provides a sufficient basis for recognition. Alion recognizes revenue on claims as expenses are incurred and only to the extent it is probable we will recover such costs and can reliably estimate the amount we will recover.
			Income Taxes
			Alion accounts for income taxes by applying the provisions in currently enacted tax laws. We determine deferred income taxes based on the estimated future tax effects of differences between the financial statement and tax bases of our assets and liabilities. Deferred income tax provisions and benefits change as assets or liabilities change from year to year. In providing for deferred taxes, Alion considers the tax regulations of the jurisdictions where we operate; estimated future taxable income; and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies change, the carrying value of deferred tax assets and liabilities may require adjustment.
			Alion has a history of operating losses for both tax and financial statement purposes. The Company has recorded valuation allowances equal to deferred tax assets based on the likelihood that we may not be able to realize the value of these assets. Alion recognizes the benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain our position following an audit. For tax positions meeting the “more likely than not” threshold, we recognize the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
			Cash and Cash Equivalents
			The Company considers cash in banks, and deposits with financial institutions with maturities of three months or less at time of purchase which it can liquidate without prior notice or penalty, to be cash and cash equivalents.
			Accounts Receivable and Billings in Excess of Revenue Earned
			Accounts receivable include billed accounts receivable and unbilled receivables. Unbilled receivables consist of costs and fees which are billable upon occurrence of a specific event, amounts billable after the balance sheet date and revenue in excess of billings on uncompleted contracts (accumulated project expenses and fees which were not billed or were not currently billable as of the date of the consolidated balance sheet). Unbilled accounts receivable include revenue recognized for customer-requested work Alion performed on new and existing contracts for which the Company had not received contracts or contract modifications. Accounts receivable are stated as estimated realized value. The allowance for doubtful accounts is Alion’s best estimate of the amount of probable losses in the Company’s existing billed and unbilled accounts receivable. The Company determines the allowance using specific identification and historical write-off experience based on receivable age. Billings in excess of revenue and advance collections from customers represent amounts received from or billed to customers in excess of project revenue recognized to date.
			Property, Plant and Equipment
			Leasehold improvements, software and equipment are recorded at cost. Maintenance and repairs that do not add significant value or significantly lengthen an asset’s useful life are charged to current operations. Software and equipment are depreciated on the straight-line method over their estimated useful lives (typically 3 years for software and 5 years for equipment). Leasehold improvements are amortized on the straight-line method over the shorter of the asset’s estimated useful life or the life of the lease. Upon sale or retirement of an asset, costs and related accumulated depreciation are deducted from the accounts, and any gain or loss is recognized in the audited consolidated statements of operations.
			Goodwill
			Alion assigns the purchase price paid to acquire the stock or assets of a business to the net assets acquired based on the estimated fair value of assets acquired and liabilities assumed. Goodwill is the purchase price in excess of the estimated fair value of the tangible net assets and separately identified intangible assets acquired. There have been no changes to goodwill carrying value this year.
			The Company accounts for goodwill and other intangible assets in accordance with the provisions of ASC 350 – Intangibles-Goodwill and Other. Alion operates in one segment and tests goodwill at the reporting unit level. There are two reporting units. We review goodwill for impairment in the fourth quarter each year, and whenever events or circumstances indicate goodwill might be impaired. We are required to recognize an impairment loss to the extent our goodwill carrying value at the reporting unit level exceeds fair value. Evaluating goodwill involves significant management estimates. To date, our annual reviews have resulted in no goodwill impairment adjustments. See Note 9 for a detailed discussion of the Company’s goodwill impairment testing process.
			Intangible Assets
		Alion amortizes intangible assets as it consumes economic benefits over estimated useful lives. As of September 30, 2013, the Company had approximately $2.0 million in net intangible assets, including contracts purchased in the JJMA acquisition and purchased software licenses. The JJMA contract portfolio has a remaining useful life of approximately 1.6 years.
		Redeemable Common Stock
		There is no public market for Alion’s redeemable common stock and therefore no observable price for its equity, individually or in the aggregate. The Employee Stock Ownership Plan (ESOP) Trust holds all the Company’s outstanding common stock. Under certain circumstances, ESOP beneficiaries can require the ESOP Trust to distribute the value of their beneficial interests. The Internal Revenue Code (IRC) and the Employee Retirement Income Security Act (ERISA) require the Company to offer ESOP participants who receive Alion common stock a liquidity put right. The put right requires the Company to purchase distributed shares at their then-current fair market value at any time during two put option periods. Common stock distributed by the ESOP Trust is subject to a right of first refusal. Prior to any subsequent transfer, shares must first be offered to the Company and then to the ESOP Trust. Eventual redemption of shares of Alion common stock as a result of distributions is outside the Company’s control. Therefore, Alion classifies its outstanding shares of redeemable common stock as other than permanent equity.
		At each reporting date, Alion is required to increase or decrease the reported value of its outstanding common stock to reflect its estimated redemption value. Management estimates the value of Alion’s obligation to repurchase its outstanding shares of redeemable common stock by considering, in part, the most recent price at which the Company was able to sell shares to the ESOP Trust. The reported value of outstanding redeemable common stock equals the current share price multiplied by total shares issued and outstanding.
		In its fiduciary capacity, the ESOP Trustee is independent of the Company and its management. Consistent with its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the ESOP Trustee may acquire or dispose of investments in Alion common stock. The Audit and Finance Committee of Alion’s Board of Directors reviews the reasonableness of the amount management has determined Alion should recognize for the Company’s obligation to repurchase shares of its outstanding redeemable common stock. The Audit and Finance Committee considers various factors in its review, including, in part, the most recent valuation report prepared for, and the share price selected by the ESOP Trustee.
		Alion records changes in the reported value of its outstanding common stock through an offsetting charge or credit to accumulated deficit. The Company recognizes changes in the fair value of its redeemable common stock on March 31 and September 30 each year. The accumulated deficit at September 30, 2013, included a $67.5 million cumulative benefit for changes in share price which reduced the Company’s aggregate share redemption obligation. Outstanding redeemable common stock had an aggregate fair value of approximately $61.9 million as of September 30, 2013.
		Concentration of Credit Risk
		Alion is subject to credit risk for its cash equivalents and accounts receivable. The Company believes the high credit quality of its cash equivalent investments limits its credit risk with respect to such investments. Alion believes its concentration of credit risk with respect to accounts receivable is limited as the receivables are principally due from the federal government. Approximately 22% of the Company’s receivables are due from commercial customers including other prime contractors.
		Fair Value of Financial Instruments
		Alion is required to disclose the fair value of its financial instruments, but is not required to record its senior long term debt at fair value. See Note 11 for a discussion of Alion’s long term debt and Note 12 for the related fair value disclosures. The fair value of cash, cash equivalents, accounts payable and accounts receivable is not materially different from carrying value because of the short maturity of those instruments.
		Off-Balance Sheet Financing Arrangements
		Alion accounts for operating leases entered into in the routine course of business in accordance with ASC 840 Leases. We have no off-balance sheet financing arrangements other than operating leases and letters of credit under our revolving credit facility. Alion has no relationship with any unconsolidated or special purpose entity and has not issued any guarantees.
		Recently Issued Accounting Pronouncements
		In July 2013, FASB issued Accounting Standards Update 2013-11 (ASU 2013-11)—Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. ASU 2013-11 updates Accounting Standards Codification Topic 740 – Income Taxes and is intended to eliminate diversity in accounting practice. In general, ASU 2013-11 requires an entity to reduce deferred tax assets for unrecognized tax benefits related to net operating loss or tax credit carryforwards. An entity is to present unrecognized tax benefits as a liability when: (1) the related net operating loss or tax credit carryforward is unavailable to settle the liability; or (2) tax law permits and the entity intends not to use its deferred tax assets to offset taxes arising from disallowing the entity’s tax position. ASU 2013-11 affects presentation of amounts and does not affect income tax expense. Management does not believe that adopting ASU 2013-11 will affect the Company’s operating results, financial position or cash flows.
		In January 2013, the FASB issued Accounting Standards Update 2013-01 (ASU 2013-01) Balance Sheet Topic (Topic 210)—Clarifying the Scope and Disclosures About Offsetting Assets and Liabilities. ASU 2013-01 is effective for fiscal years beginning after January 1, 2013 and provides guidance on what disclosures to make about offsetting balances. Alion currently does not offset any significant balances and has no related disclosure. The Company does not believe adopting ASU 2013-01 will affect Alion’s consolidated financial position or operating results.

Employee_Stock_Ownership_Plan_

Employee Stock Ownership Plan (ESOP) and ESOP Trust	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Text Block [Abstract]	'		'
Employee Stock Ownership Plan (ESOP) and ESOP Trust	'		'
	-3	Employee Stock Ownership Plan (ESOP) and ESOP Trust	(4) Employee Stock Ownership Plan (ESOP) and ESOP Trust
	In December 2001, the Company adopted the Alion Science and Technology Corporation Employee Ownership, Savings and Investment Plan (the Plan, the KSOP) and established the ESOP Trust. The Plan, a tax qualified retirement plan, includes an ESOP and a 401(k) component. In April 2010, the Internal Revenue Service (IRS) issued a determination letter that the ESOP Trust and the Plan, as amended and restated as of October 1, 2006, including Plan amendments executed in June 2009 and May 2010 qualify under IRC Sections 401(a) and 501(a).		In December 2001, the Company adopted the Alion Science and Technology Corporation Employee Ownership, Savings and Investment Plan (the Plan, the KSOP) and established the ESOP Trust. The Plan, a tax qualified retirement plan, includes an ESOP and a 401(k) component. In April 2010, the Internal Revenue Service (IRS) issued a determination letter that the ESOP Trust and the Plan, as amended and restated as of October 1, 2006, including Plan amendments executed in June 2009 and May 2010 qualify under IRC Sections 401(a) and 501(a).
	In August 2008, Alion amended the Trust Agreement between the Company and the ESOP Trust. In June 2011, the Company amended the Plan to eliminate the one year service requirement for employer 401(k) matching contributions; to automatically enroll new hires in the Plan’s 401(k) component; and to designate profit sharing contributions exclusively in Alion common stock.		In August 2008, Alion amended the Trust Agreement between the Company and the ESOP Trust. In June 2011, the Company amended the Plan to eliminate the one year service requirement for employer 401(k) matching contributions; to automatically enroll new hires in the Plan’s 401(k) component; and to designate profit sharing contributions exclusively in Alion common stock.
	In September 2013, Alion amended the Plan to delay transfer to the Company of employee contributions for investment in the ESOP component of the Plan and to delay the Company’s contribution to the Plan for the six months ended September 30, 2013. The September 2013 amendment permitted delaying the valuation of Alion’s common stock until the due date (including extensions) for filing the Company’s federal tax return for the current fiscal year. The Company believes the Plan and the ESOP Trust have been designed and are being operated in compliance with applicable IRC requirements.		In September 2013, Alion amended the Plan to delay transfer to the Company of employee contributions for investment in the ESOP component of the Plan and to delay the Company’s contribution to the Plan for the six months ended September 30, 2013. The September 2013 amendment also delayed the valuation of Alion’s common stock until the due date (including extensions) for filing the Company’s federal tax return for the current fiscal year. The Company believes the Plan and the ESOP Trust have been designed and are being operated in compliance with applicable IRC requirements.

Loss_Per_Share

Loss Per Share	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Earnings Per Share [Abstract]	'		'
Loss Per Share	'		'
	-4	Loss Per Share	(5) Loss Per Share
	Basic and diluted loss per share is computed by dividing net loss by the weighted average number of common shares outstanding excluding the impact of warrants. Warrants are anti-dilutive for all periods presented even after including required adjustments to the earnings per share numerator. On March 22, 2010, Alion issued 310,000 Units that included the Secured Notes and warrants to purchase 602,614 shares of Alion common stock The Secured Note warrants have a penny per share exercise price, are currently exercisable and expire March 15, 2017. The Secured Note warrants are not redeemable or puttable; they are classified as permanent equity.		Basic and diluted loss per share is computed by dividing net loss by the weighted average number of common shares outstanding excluding the impact of warrants. The warrants are anti-dilutive for all periods presented even after including required adjustments to the earnings per share numerator. On March 22, 2010, Alion issued 310,000 Units that included the Secured Notes and warrants to purchase 602,614 shares of Alion common stock The Secured Note warrants have a penny per share exercise price, are currently exercisable and expire March 15, 2017. The Secured Note warrants are not redeemable or puttable; they are classified as permanent equity.

Redeemable_Common_Stock

Redeemable Common Stock	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Text Block [Abstract]	'		'
Redeemable Common Stock	'		'
	-5	Redeemable Common Stock
	The ESOP Trust owns all of Alion’s issued and outstanding common stock, for the benefit of current and former employee participants in the Alion KSOP. Participants and beneficiaries are entitled to a distribution of the fair value of their vested ESOP account balance upon death, disability, retirement or termination of employment. The Plan permits distributions to be paid over a five year period commencing the first ESOP valuation after a participant’s retirement at age 65, death or disability. Alion can delay distributions to other terminating participants for six years before commencing payment over a subsequent five year period. The Company intends to pay distribution requests in annual installments and defer initial payments as permitted.		(6) Redeemable Common Stock
	Terminating ESOP participants can hold or immediately sell their distributed shares to the Company. If a participant elects to hold distributed shares, the IRC and ERISA require Alion to offer a put option to allow the recipient to sell stock to Alion at the estimated fair value share price based on the most recent price at which the Company was able to sell shares to the ESOP Trust ($16.25 at March 31, 2013 and $8.10 at September 30, 2013). The put right requires Alion to purchase distributed shares during two put option periods at then-current fair market value.		The ESOP Trust owns all of Alion's issued and outstanding common stock, for the benefit of current and former employee participants in the Alion KSOP. Participants and beneficiaries are entitled to a distribution of the fair value of their vested ESOP account balance upon death, disability, retirement or termination of employment. The Plan permits distributions to be paid over a five year period commencing the year after a participant's retirement at age 65, death or disability. Alion can delay distributions to other terminating participants for six years before commencing payment over a subsequent five year period. The Company intends to pay distribution requests in annual installments and defer initial payments as permitted.
	Consistent with its duty of independence from Alion management and its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the Trustee may acquire or dispose of investments in Alion common stock. The September 30, 2013 valuation occurred on its normal schedule.
	Alion management determines, and the Board of Directors’ Audit and Finance Committee reviews, the reasonableness of Alion’s recorded redeemable common stock liability. The Audit and Finance Committee considers various factors in its review, including in part, the ESOP valuation report and the share price selected by the ESOP Trustee. Management considers the share price selected by the ESOP Trustee along with other factors in estimating Alion’s aggregate liability for outstanding redeemable common stock.		Terminating ESOP participants can hold or immediately sell their distributed shares to the Company. If a participant elects to hold distributed shares, the IRC and ERISA require Alion to offer a put option to allow the recipient to sell stock to Alion at the estimated fair value share price based on the most recent price at which the Company was able to sell shares to the ESOP Trust ($16.25 at March 31, 2013 and $8.10 at September 30, 2013). The put right requires Alion to purchase distributed shares during two put option periods at then-current fair market value.
			Consistent with its duty of independence from Alion management and its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the Trustee may acquire or dispose of investments in Alion common stock. In September 2013, Alion amended the Plan to delay the semi-annual September 30th valuation of Alion's common stock until the due date (including extensions) for filing the Company's federal tax return for the current fiscal year. The semi-annual valuation of the Company's common stock was delayed due to the then uncertainty surrounding the refinancing of the Company's outstanding debt. The ESOP trustee, the board of directors and executive management team believed that it was in the best interest of the ESOP participants to delay the valuation until the framework of the refinancing transactions was announced. The valuation was completed in December of 2013. The Company estimates that the aggregate ESOP repurchase obligations for the next five years is approximately $14 million.
			Alion management determines, and the Board of Directors' Audit and Finance Committee reviews, the reasonableness of Alion's recorded redeemable common stock liability. The Audit and Finance Committee considers various factors in its review, including in part, the ESOP valuation report and the share price selected by the ESOP Trustee. Management considers the share price selected by the ESOP Trustee along with other factors in estimating Alion's aggregate liability for outstanding redeemable common stock.
			A limited number of participants who beneficially acquired shares of Alion common stock on December 20, 2002, can sell such shares distributed from their accounts at the greater of $10.00 or the current estimated fair value share price. Although the Company and the ESOP retain the right to delay distributions consistent with the terms of the Plan, and to control the circumstances of future distributions, eventual redemption of shares of Alion common stock is deemed to be outside the Company's control.

Accounts_Receivable

Accounts Receivable	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Receivables [Abstract]	'							'
Accounts Receivable	'							'
	(6) Accounts Receivable							(7) Accounts Receivable
	Accounts receivable at December 31, 2013 and September 30, 2013 consisted of the following:							Accounts receivable at September 30 consisted of the following:
		December 31,			September 30,				September 30,
		2013			2013				2013			2012
		(In thousands)							(In thousands)
	Billed receivables and amounts billable as of the balance sheet date	$	104,581		$	102,211		Billed receivables and amounts billable as of the balance sheet date	$	102,211		$	94,028
	Unbilled receivables:							Unbilled receivables:
	Amounts billable after the balance sheet date		28,107			36,693		Amounts billable after the balance sheet date		36,693			48,730
	Revenues recorded in excess of milestone billings on fixed price contracts		3,825			3,289		Revenues recorded in excess of milestone billings on fixed price contracts		3,289			2,666
	Revenues recorded in excess of estimated contract value or funding		17,803			14,605		Revenues recorded in excess of estimated contract value or funding		14,605			18,998
	Retainages and other amounts billable upon contract completion		18,635			19,557		Retainages and other amounts billable upon contract completion		19,557			15,016
	Allowance for doubtful accounts		(3,988	)		(3,751	)	Allowance for doubtful accounts		(3,751	)		(4,145	)
	Total Accounts Receivable	$	168,963		$	172,604		Total Accounts Receivable	$	172,604		$	175,293
	Billed accounts receivable include invoices issued to customers for services performed as of the balance sheet date. Unbilled accounts receivable represent revenue recognized as of the balance sheet date for which Alion has yet to issue invoices to customers. Amounts that are currently billable are expected to be invoiced to customers within the next twelve months. Fixed-price contract revenue in excess of milestone billings is not yet contractually billable. Revenue in excess of contract value or funding is billable when Alion receives contract amendments or modifications. Approximately $135.8 million (79%) and $137.5 million (78%) of contract receivables at December 31, 2013 and September 30, 2013 were from federal government prime contracts.							Billed accounts receivable include invoices issued to customers for services performed as of the balance sheet date. Unbilled accounts receivable represent revenue recognized as of the balance sheet date for which Alion has yet to issue invoices to customers. Amounts that are currently billable are expected to be invoiced to customers within the next twelve months. Fixed-price contract revenue in excess of milestone billings is not yet contractually billable. Revenue in excess of contract value or funding is billable when Alion receives contract amendments or modifications. Approximately $137.5 million (78%) and $138.9 million (77%) of contract receivables at September 30, 2013 and September 30, 2012 were from federal government prime contracts.
	At December 31, 2013, Alion recognized $68.4 million in revenue in excess of billings on uncompleted contracts including approximately $17.8 million for customer-requested work for which the Company had not received contracts or contract modifications. At September 30, 2013, Alion had recognized $74.1 million in revenue in excess of billings on uncompleted contracts including approximately $14.6 million for customer-requested work for which the Company had not received contracts or contract modifications.							At September 30, 2013, Alion recognized $74.1 million in revenue in excess of billings on uncompleted contracts including approximately $14.6 million for customer-requested work for which the Company had not received contracts or contract modifications. At September 30, 2012, Alion had recognized $85.4 million in revenue in excess of billings on uncompleted contracts including approximately $19.0 million for customer-requested work for which the Company had not received contracts or contract modifications.
	Retainages and other unbilled amounts are billable upon contract completion or completion of DCAA audits. In keeping with industry practice, Alion classifies all contract-related accounts receivable as current assets based on contractual operating cycles which frequently exceed one year. Except for $18.6 million at December 31, 2013, the Company expects to invoice and collect unbilled receivables within the next twelve months.							Retainages and other unbilled amounts are billable upon contract completion or completion of DCAA audits. In keeping with industry practice, Alion classifies all contract-related accounts receivable as current assets based on contractual operating cycles which frequently exceed one year. Except for $19.6 million at September 30, 2013, the Company expects to invoice and collect unbilled receivables within the next twelve months.

Property_Plant_and_Equipment

Property, Plant and Equipment	3 Months Ended								12 Months Ended
	Dec. 31, 2013								Sep. 30, 2013
Property Plant And Equipment [Abstract]	'								'
Property, Plant and Equipment	'								'
	-7	Property, Plant and Equipment							(8) Property, Plant and Equipment
			December 31,			September 30,				September 30,
			2013			2013				2013			2012
			(In thousands)							(In thousands)
	Leasehold improvements		$	12,603		$	12,984		Leasehold improvements	$	12,984		$	12,168
	Equipment and software			35,314			35,203		Equipment and software		35,203			35,562
	Total cost			47,917			48,187		Total cost		48,187			47,730
	Less: accumulated depreciation and amortization			(38,847	)		(38,519	)	Less: accumulated depreciation and amortization		(38,519	)		(37,125	)
	Net Property, Plant and Equipment		$	9,070		$	9,668		Net Property, Plant and Equipment	$	9,668		$	10,605
	Depreciation for fixed assets and leasehold amortization expense was approximately $778 thousand and $788 thousand for the quarters ended December 31, 2013 and 2012.								Depreciation and leasehold amortization expense for fixed assets was approximately $3.3 million, $4.3 million, and $4.4 million for the years ended September 30, 2013, 2012, and 2011.

Goodwill

Goodwill	3 Months Ended			12 Months Ended
	Dec. 31, 2013			Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'			'
Goodwill	'			'
	-8	Goodwill		(9) Goodwill
	The Company accounts for goodwill and other intangible assets according to ASC 350 Intangibles – Goodwill and Other (ASC 350) which requires that Alion review goodwill at least annually for impairment or more frequently if events or circumstances indicate goodwill might be impaired. The Company performs this review at the end of each fiscal year. As of September 30, 2013, Alion had approximately $398.9 million in goodwill. There were no changes to the goodwill carrying amount for the years ended September 30, 2012 and 2011, nor were there any significant events this year that indicated a potential impairment to goodwill as of September 30, 2013.			The Company accounts for goodwill and other intangible assets according to ASC 350 Intangibles – Goodwill and Other (ASC 350) which requires that Alion review goodwill at least annually for impairment or more frequently if events or circumstances indicate goodwill might be impaired. The Company performs this review at the end of each fiscal year. As of September 30, 2013, Alion had approximately $398.9 million in goodwill. There were no changes to the goodwill carrying amount for the years ended September 30, 2012 and 2011, nor were there any significant events this year that indicated a potential impairment to goodwill as of September 30, 2013.
	Alion operates in one segment and tests goodwill at the reporting unit level. Each of Alion’s two reporting units delivers a similar set of professional engineering, scientific and technical services to a wide array of federal government customers, principally within the Department of Defense. Each reporting unit provides the full range of services Alion offers to customers overall.			Alion operates in one segment and tests goodwill at the reporting unit level. Each of Alion’s two reporting units delivers a similar set of professional engineering, scientific and technical services to a wide array of federal government customers, principally within the Department of Defense. Each reporting unit provides the full range of services Alion offers to customers overall.
	Alion’s management has organized reporting units based on managerial responsibility and administrative structure, contract portfolios, and the availability of discrete financial information. Management evaluates reporting unit financial performance based on contract revenue and non-GAAP operating income. Alion does not maintain reporting unit balance sheets and does not track cash flows by reporting unit.			Alion’s management has organized reporting units based on managerial responsibility and administrative structure, contract portfolios, and the availability of discrete financial information. Management evaluates reporting unit financial performance based on contract revenue and non-GAAP operating income. Alion does not maintain reporting unit balance sheets and does not track cash flows by reporting unit.
	Management identifies reporting units as “sectors” which in turn include lower level business units identified as “groups” consisting of still lower level “operations.” For each business combination, management assigned the goodwill arising from acquisitions to the reporting unit or units expected to benefit from the synergies of that business combination. Coincident with its goodwill determination and purchase price allocation, management assigned assets acquired to reporting units based on the unit or units anticipated to utilize such assets. Management did not allocate to reporting units the liabilities arising from business combinations. Alion’s reporting units are the Engineering and Integration Solutions Sector (EISS) and the Technology, Engineering and Operational Solutions Sector (TEOSS). Management assigned $197.0 million in goodwill to EISS and $201.9 million in goodwill to TEOSS.			Management identifies reporting units as “sectors” which in turn include lower level business units identified as “groups” consisting of still lower level “operations.” For each business combination, management assigned the goodwill arising from acquisitions to the reporting unit or units expected to benefit from the synergies of each business combination. Coincident with its goodwill determination and purchase price allocation, management assigned assets acquired to reporting units based on the unit or units anticipated to utilize such assets. Management did not allocate to reporting units the liabilities arising from business combinations. Alion’s reporting units are the Engineering and Integration Solutions Sector (EISS) and the Technology, Engineering and Operational Solutions Sector (TEOSS). Management assigned $197.0 million in goodwill to EISS and $201.9 million in goodwill to TEOSS.
	In 2013, TEOSS had $477 million in contract revenue and EISS had $371 million in contract revenue. Total contract revenue for all reporting units does not equal Alion’s total reported revenue because reporting unit contract revenue does not include $292 thousand in inter-company eliminations, discounts, and GSA industrial funding fees which the Company does not track by reporting unit.			In 2013, TEOSS had $477 million in contract revenue and EISS had $371 million in contract revenue. In 2012, TEOSS had $435 million in contract revenue EISS had $386 million in contract revenue. Total contract revenue for all reporting units does not equal Alion’s total reported revenue because reporting unit contract revenue does not include the effects of inter-company eliminations, discounts and GSA industrial funding fees that the Company does not track by reporting unit. These amounts were $292 thousand in 2013 and $703 thousand in 2012.
	Management applied the guidance in ASC 350 and the related guidance in ASC Topic 280 Segment Reporting to analyze Alion’s reporting units to determine the appropriate level at which to test goodwill for potential impairment. The Company employs a reasonable, supportable and consistent method to assign goodwill to reporting units expected to benefit from the synergies arising from acquisitions. Alion determined reporting unit goodwill in a manner similar to the way it determines goodwill in a purchase allocation by using fair value to determine reporting unit purchase price, assets, liabilities and goodwill. Reporting unit residual fair value after this allocation is the implied fair value of reporting unit goodwill. The Company allocates the goodwill related to acquisitions on a specific identification basis consistent with reporting unit structure.			Management applied the guidance in ASC 350 and the related guidance in ASC Topic 280 Segment Reporting to analyze Alion’s reporting units to determine the appropriate level at which to test goodwill for potential impairment. The Company employs a reasonable, supportable and consistent method to assign goodwill to reporting units expected to benefit from the synergies arising from acquisitions. Alion determined reporting unit goodwill in a manner similar to the way it determines goodwill in a purchase allocation by using fair value to determine reporting unit purchase price, assets, liabilities and goodwill. Reporting unit residual fair value after this allocation is the implied fair value of reporting unit goodwill. The Company allocates the goodwill related to acquisitions on a specific identification basis consistent with reporting unit structure.
	The Company performs its own independent analysis to determine whether goodwill is potentially impaired. Management performs a discounted cash flow analysis to determine the fair value of each reporting unit. The Company compares the aggregated fair value per the discounted cash flow model to the fair value indicated by the market multiples used in the stock valuation. Management independently determines the rates and assumptions it uses to: perform its goodwill impairment analysis; assess the probability of future contracts and revenue; and evaluate the recoverability of goodwill. At September 30, 2013, executed contract backlog was approximately 2.6 times trailing twelve month revenue.			The Company performs its own independent analysis to determine whether goodwill is potentially impaired. Management performs a discounted cash flow analysis to determine the fair value of each reporting unit. The Company compares the aggregated fair value per the discounted cash flow model to the fair value indicated by the market multiples used in the stock valuation. Management independently determines the rates and assumptions it uses to: perform its goodwill impairment analysis; assess the probability of future contracts and revenue; and evaluate the recoverability of goodwill. At September 2013, executed contract backlog was approximately 2.6 times trailing twelve month revenue. Executed backlog at September 2012 was 2.9 times trailing twelve month revenue.
	Alion’s cash flow analysis depends on several significant management inputs and assumptions. Management uses observable inputs, rates and assumptions generally consistent with those used by the independent third party to prepare the valuation report for the ESOP Trustee. However, management’s sensitivity analyses also incorporated a more conservative range of growth assumptions in addition to assumptions generally consistent with those used by the independent third party to prepare the valuation report for the ESOP Trust. These sensitivity analyses are designed to stress management’s best estimate of the Company’s financial forecast for purposes of understanding whether a reasonable decline in growth would cause the associated expected discounted cash flows to fall below the reporting units’ carrying value. Management’s cash flow analysis includes the following significant inputs and assumptions: estimated future revenue and revenue growth; estimated future operating margins and EBITDA; observable market multiples for comparable companies; and a discount rate management believes is consistent with a market-based weighted average cost of capital. Management includes EBITDA in its analysis in order to use publicly available valuation data.			Alion’s cash flow analysis depends on several significant management inputs and assumptions. Management uses observable inputs, rates and assumptions generally consistent with those used by the independent third party to prepare the valuation report for the ESOP Trustee. However, management’s sensitivity analyses also incorporated a more conservative range of growth assumptions in addition to assumptions generally consistent with those used by the independent third party to prepare the valuation report for the ESOP Trust. These sensitivity analyses are designed to stress management’s best estimate of the Company’s financial forecast for purposes of understanding whether a reasonable decline in growth would cause the associated expected discounted cash flows to be below the reporting units’ carrying value. Management’s cash flow analysis includes the following significant inputs and assumptions: estimated future revenue and revenue growth; estimated future operating margins and EBITDA; observable market multiples for comparable companies; and a discount rate consistent with a market-based weighted average cost of capital. Management includes EBITDA in its analysis in order to use publicly available valuation data.
	In Alion’s impairment testing in fiscal 2013, market multiples for trailing twelve month EBITDA for comparable companies (publicly traded professional services government contractors) ranged from a low of 7.6 to a high of 18.2, with a median value of 13.4. Market multiples for trailing twelve month revenue ranged from a low of 0.30 to a high of 3.01, with a median value of 1.36. Management based its goodwill impairment testing valuation on discounted cash flows, and revenue and EBITDA multiples. Management discounted median market multiples by approximately 30% to reflect Alion’s recent financial performance compared to its peers and the significant uncertainties in the professional services government contracting marketplace likely to adversely affect future financial performance. Management used a weighted average cost of capital rate of 13.0% derived from market-based inputs, the tax-effected interest cost of Alion’s outstanding debt and a hypothetical market participant capital structure. Management estimates future years’ EBITDA based on Alion’s reporting units’ historical adjusted EBITDA as a percentage of revenue. To the extent that management’s analysis included forecasts of future revenue growth, management based such estimates on existing contract backlog, recent contract wins, current year performance and new business opportunities. Management analyzed goodwill for impairment using a range of near-term growth values of 0-4% and a range of 0-4% for longer-term out year forecasts.
	There were no changes to the methods used to evaluate goodwill in prior periods. Changes in one or more inputs could materially alter the calculation of Alion’s enterprise fair value and thus the Company’s determination of whether its goodwill is potentially impaired. A hypothetical 10% increase or decrease in the weighted average cost of capital rate at September 30, 2013, would have produced a corresponding approximate 5.7% decrease and 6.9% increase in estimated enterprise value. Alion’s enterprise value based on EBITDA multiples from mergers and acquisitions in the government services market place was approximately 26% higher than discounted cash flow enterprise value at September 30, 2013.			In Alion’s impairment testing in fiscal 2013, market multiples for trailing twelve month EBITDA for comparable companies (publicly traded professional services government contractors) ranged from a low of 7.6 to a high of 18.2, with a median value of 13.4. Market multiples for trailing twelve month revenue ranged from a low of 0.30 to a high of 3.01, with a median value of 1.36. Management based its goodwill impairment testing valuation on discounted cash flows, and revenue and EBITDA multiples. Management discounted median market multiples by approximately 30% to reflect Alion’s recent financial performance compared to its peers and the significant uncertainties in the professional services government contracting marketplace likely to adversely affect future financial performance. Management used a weighted average cost of capital rate of 13.0% derived from market-based inputs, the tax-effected interest cost of Alion’s outstanding debt and a hypothetical market participant capital structure. Management estimates future years’ EBITDA based on Alion’s reporting units’ historical adjusted EBITDA as a percentage of revenue. To the extent that management’s analysis included forecasts of future revenue growth, management based such estimates on existing contract backlog, recent contract wins, current year performance and new business opportunities. Management analyzed goodwill for impairment using a range of near-term growth values of 0-4% and a range of 0-4% for longer-term out year forecasts.
	Management reviews the Company’s internally-computed enterprise fair value to confirm the reasonableness of the internal analysis and compares the results of its independent analysis with the results of the independent third party valuation report prepared for the ESOP Trustee. Management compares each reporting unit’s carrying amount to its estimated fair value. If a reporting unit’s carrying value exceeds its estimated fair value, the Company compares the reporting unit’s goodwill carrying amount with the corresponding implied fair value of its goodwill. If the carrying amount of reporting unit goodwill exceeds its fair value, the Company recognizes an impairment loss to the extent that the carrying amount of goodwill exceeds implied fair value. Alion performs impairment testing on an enterprise value basis as there is no public market for the Company’s common stock.			In Alion’s impairment testing in fiscal 2012, market multiples for trailing twelve month EBITDA for comparable companies (publicly traded professional services government contractors) ranged from a low of 5.6 to a high of 18.2, with a median value of 12.8. Market multiples for trailing twelve month revenue ranged from a low of 0.3 to a high of 3.02, with a median value of 1.32. Management based its goodwill impairment testing valuation on discounted cash flows, and revenue and EBITDA multiples. Management discounted median market multiples by 14%-40% to reflect Alion’s recent financial performance compared to its peers and the significant uncertainties in the professional services government contracting marketplace likely to adversely affect future financial performance. Management used a weighted average cost of capital rate of 12.5% derived from market-based inputs, the tax-effected interest cost of Alion’s outstanding debt and a hypothetical market participant capital structure. Management estimates future years’ EBITDA based on Alion’s historical adjusted EBITDA as a percentage of revenue. To the extent that management’s analysis included forecasts of future revenue growth, management based such estimates on existing contract backlog, recent contract wins, current year performance and new business opportunities. Management analyzed goodwill for impairment using a range of near-term growth values of 0-1% and a range of 0-2% for longer-term out year forecasts.
	Management determined that, on an enterprise value basis, Alion’s reporting units have positive carrying value. In reviewing its discounted cash flow analysis prepared for testing goodwill for potential impairment, management considered macroeconomic and other conditions such as:			There were no changes to the methods used to evaluate goodwill in prior periods. Changes in one or more inputs could materially alter the calculation of Alion’s enterprise fair value and thus the Company’s determination of whether its goodwill is potentially impaired. A hypothetical 10% increase or decrease in the weighted average cost of capital rate at September 30, 2013, would have produced a corresponding approximate 5.7% decrease and 6.9% increase in estimated enterprise value. Alion’s enterprise value based on EBITDA multiples from mergers and acquisitions in the government services market place was approximately 26% higher than discounted cash flow enterprise value at September 30, 2013.
				Management reviews the Company’s internally-computed enterprise fair value to confirm the reasonableness of the internal analysis and compares the results of its independent analysis with the results of the independent third party valuation report prepared for the ESOP Trustee. Management compares each reporting unit’s carrying amount to its estimated fair value. If a reporting unit’s carrying value exceeds its estimated fair value, the Company compares the reporting unit’s goodwill carrying amount with the corresponding implied fair value of its goodwill. If the carrying amount of reporting unit goodwill exceeds its fair value, the Company recognizes an impairment loss to the extent that the carrying amount of goodwill exceeds implied fair value. Alion performs impairment testing on an enterprise value basis as there is no public market for the Company’s common stock.
		•	the deterioration in general economic conditions arising from federal budget deficits;	Management determined that, on an enterprise value basis, Alion’s reporting units have positive carrying value. In reviewing its discounted cash flow analysis prepared for testing goodwill for potential impairment, management considered macroeconomic and other conditions such as:
		•	Industry and market concerns about the effects of sequestration and federal budget deficits on future Department of Defense procurement actions;		•	the deterioration in general economic conditions arising from federal budget deficits;
		•	Alion’s credit rating and its potential for limiting future access to capital;		•	Defense and aerospace industry and market concerns about the effects of sequestration and federal budget deficits on future Department of Defense procurement actions;
		•	An increase in market risks		•	Alion’s credit rating and its potential for limiting future access to capital;
					•	An increase in market risks
		•	A higher discount rate for valuing estimated future cash flows;
					•	A higher discount rate for valuing estimated future cash flows;
		•	A decline in market-dependent multiples and metrics in both absolute terms and for Alion relative to its peers;
					•	A decline in market-dependent multiples and metrics in both absolute terms and for Alion relative to its peers;
		•	Alion’s fiscal 2013 sales increase; and
					•	Alion’s current year sales increase compared to last year; and
		•	Alion’s success in obtaining $840 million of additional customer contract funding and new contracts from April through September 30, 2013.
	Alion completed its most recent goodwill impairment analysis in the fourth quarter of fiscal year 2013 and concluded no goodwill impairment existed as of September 30, 2013. Management determined the totality of events and circumstances would not have supported a decision to roll forward its prior year goodwill impairment analysis and avoid performing a step one goodwill impairment analysis. Management chose to perform a step one analysis which supported a comparable enterprise value for Alion as of September 30, 2013 compared to September 30, 2012. September 30, 2013 estimated discounted future cash flows decreased less than 1.0% compared to September 30, 2012. The estimated fair value of Alion’s outstanding debt increased approximately 10 percent from September 30, 2012 to September 30, 2013. This was due to shortening maturities and a higher outstanding balance for secured debt and notwithstanding fiscal 2013 unsecured debt redemptions. As a result of changes in Alion’s estimated enterprise fair value and the increased value of Alion’s outstanding debt, the estimated fair value of Alion’s outstanding redeemable common stock declined approximately 50% from September 30, 2012 to September 30, 2013.				•	Alion’s success in obtaining $840 million of additional customer contract funding and new contracts in the past six months.
	As of September 30, 2013, the estimated fair value of each reporting unit exceeded its carrying value. Consistent with prior years’ disclosures, the changes in discounted cash flows for fiscal 2013 compared to fiscal 2012 did not result in an impairment to goodwill. The results of Alion’s step one impairment testing make it unlikely that a reasonably probable change in assumptions would have triggered an impairment. A hypothetical 10% decrease in fair value would not have resulted in impairment to goodwill for either reporting unit or triggered the need to perform additional step two analyses for either reporting unit.			Alion completed its most recent goodwill impairment analysis in the fourth quarter of fiscal year 2013 and concluded no goodwill impairment existed as of September 30, 2013. Management determined the totality of events and circumstances would not have supported a decision to roll forward its prior year goodwill impairment analysis and avoid performing a step one goodwill impairment analysis. Management chose to perform a step one analysis which supported a comparable enterprise value for Alion as of September 2013 compared to September 2012. September 2013 estimated discounted future cash flows decreased less than 1.0% compared to September 2012. The estimated fair value of Alion’s outstanding debt increased approximately 10 percent from September 2012 to September 2013. This was due to shortening maturities and a higher outstanding balance for secured debt and notwithstanding current year unsecured debt redemptions. As a result of changes in Alion’s estimated enterprise fair value and the increased value of Alion’s outstanding debt, the estimated fair value of Alion’s outstanding redeemable common stock declined approximately 50% from September 2012 to September 2013.
				As of September 30, 2013, the estimated fair value of each reporting unit exceeded its carrying value. Consistent with prior years’ disclosures, the changes in discounted cash flows for fiscal 2013 compared to fiscal 2012 did not result in an impairment to goodwill. The results of Alion’s step one impairment testing make it unlikely that a reasonably probable change in assumptions would have triggered an impairment. A hypothetical 10% decrease in fair value would not have resulted in impairment to goodwill for either reporting unit or triggered the need to perform additional step two analyses for either reporting unit.

Intangible_Assets

Intangible Assets	3 Months Ended																12 Months Ended
	Dec. 31, 2013																Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'																'
Intangible Assets	'																'
	-9	Intangible Assets															(10) Intangible Assets
	Intangible assets consist primarily of contracts acquired through the Anteon and JJMA transactions. The table below shows intangible assets as of December 31, 2013 and September 30, 2013.																The Company accounts for intangible assets according to ASC 350 Intangibles – Goodwill and Other. Intangible assets consist primarily of contracts acquired in the JJMA transaction. The table below shows the intangible assets as of September 30, 2013 and 2012.
			December 31, 2013							September 30, 2013								September 30, 2013							September 30, 2012
			Gross		Accumulated			Net		Gross		Accumulated			Net			Gross		Accumulated			Net		Gross		Accumulated			Net
					Amortization							Amortization								Amortization							Amortization
			(In thousands)															(In thousands)
	Purchased contracts		$	111,635	$	(110,015	)	$	1,620	$	111,635	$	(109,795	)	$	1,840	Purchased contracts	$	111,635		(109,795	)		1,840	$	111,635	$	(106,935	)	$	4,700
	Internal use software and engineering designs			3,182		(3,067	)		115		3,182		(2,982	)		200	Internal use software and engineering designs		3,182		(2,982	)		200		3,182		(2,640	)		542
	Total		$	114,817	$	(113,082	)	$	1,735	$	114,817	$	(112,777	)	$	2,040	Total	$	114,817		(112,777	)		2,040	$	114,817	$	(109,575	)	$	5,242
	The weighted-average remaining amortization period of intangible assets was approximately 18 months at December 31, 2013 and September 30, 2013. Amortization expense was approximately $305 thousand and $1.5 million for the quarters ended December 31, 2013 and 2012. Estimated aggregate amortization expense for the next five years and thereafter is as follows.																The weighted-average remaining amortization period of intangible assets was approximately 20 months at September 30, 2013. Amortization expense was approximately $3.2 million, $6.5 million, and $7.0 million for the years ended September 30, 2013, 2012 and 2011. Estimated aggregate amortization expense for the next five years and thereafter is as follows.
			(In thousands)														Fiscal year ending	(In thousands)
																	September 30,
	2014 (for the remainder of the fiscal year)		$	773													2014		1,079
	2015			737													2015		736
	2016			141													2016		141
	2017			51													2017		51
	2018			33													2018		33
	2019			—
	Thereafter			—														$	2,040
			$	1,735

Current_and_LongTerm_Debt

Current and Long-Term Debt	3 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Current and Long-Term Debt	'
	-10	Current and Long-term Debt
	Alion’s existing debt structure includes a $35 million revolving credit facility (current debt), $235 million in Unsecured Notes (long-term debt) and $333.1 million in Secured Notes ($310 million in initial face value plus $23.1 million in paid in kind (PIK) interest notes issued) (current debt). The Company is in compliance with each of the affirmative, negative and financial covenants in its existing debt agreements as of December 31, 2013. In the first quarter of fiscal 2014, our Secured Notes were reclassified to current liabilities based on their November 1, 2014 maturity. Our Unsecured Notes will be reclassified to current liabilities in the second quarter of fiscal 2014. If, as of December 31, 2013, Alion had had any balance drawn under the Credit Agreement, that amount as well would have been classified as a current liability because the Credit Agreement expires on August 22, 2014.
	Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In December 2013 Alion and its Credit Agreement lenders agreed to waive this covenant for fiscal 2013 through and including February 21, 2014. The Company paid no fee for this waiver. Absent the waiver, the Company would not have been able to access its revolving credit facility. At the end of fiscal 2013, the Company had not drawn on the Credit Agreement revolving credit facility. At the date of the waiver, the Company had a balance drawn on the Credit Agreement revolving credit facility. Had the Credit Agreement lenders not granted the waiver, they would have had the right to demand the Company immediately repay any amounts outstanding under the revolving credit facility. The amount drawn on the Credit Agreement revolving credit facility was less than $30 million at the date of the waiver. Therefore, there was no potential cross default on the Company’s other outstanding indebtedness.
	Current Debt - Credit Agreement
	The Company can use its credit facility for working capital, permitted acquisitions and general corporate purposes. This includes up to $35.0 million in letters of credit and up to $5.0 million in short-term swing line loans. At December 31, 2013, the Company had $4.0 million in outstanding letters of credit and no balance actually drawn.
	Security. The Credit Agreement is secured by a first priority security interest in all current and future tangible and intangible property of Alion and its guarantor subsidiaries, IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation. In March 2010, Alion and the subsidiary guarantors entered into an Intercreditor Agreement with Wilmington Trust Company and Credit Suisse AG, Cayman Islands Branch to grant Credit Agreement lenders a super priority right of payment with respect to the underlying collateral compared to Secured Note holders’ rights.
	Guarantees. Alion’s Credit Agreement obligations are guaranteed by its subsidiaries, IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation. These subsidiaries also guarantee all the Company’s Secured Note and Unsecured Note obligations (described below).
	Interest and Fees. Alion can choose whether the Credit Agreement loans bear interest at one of two floating rates using either a Eurodollar rate or an alternative base rate. The minimum interest rate is 8.5%. The minimum Eurodollar interest rate is 2.5% plus 600 basis points. The minimum alternate base rate is 3.5% plus 500 basis points.
	Other Fees and Expenses. Each quarter, Alion pays a commitment fee of 175 basis points per year on the prior quarter’s daily unused Credit Agreement balance. The Company paid approximately $125 thousand and $142 thousand in commitment fees for the three months ended December 31, 2013 and 2012. Alion pays letter-of-credit issuance and administrative fees, and up to a 25 basis point fronting fee and interest in arrears each quarter on all outstanding letters of credit. The interest rate is based on the Eurodollar loan rate which was 6.0% as of September 30, 2013. The Company also pays an annual agent’s fee.
	Covenants. The Credit Agreement requires Alion to achieve minimum trailing twelve month Consolidated EBITDA levels which increased over the life of the agreement. The fiscal 2014 required minimum is $65.5 million through August 22, 2014.
	The Credit Agreement defines Consolidated EBITDA as net income or loss in accordance with GAAP, plus employee compensation expense payments invested in Alion common stock, plus the following items, without duplication, to the extent deducted from or included in net income or loss:
		•		consolidated interest expense;
		•		provision for income taxes;
		•		depreciation and amortization;
		•		cash contributed to the ESOP in respect of Alion’s repurchase liability;
		•		non-cash stock-based and incentive compensation expense;
		•		non-cash ESOP contributions;
		•		any extraordinary losses; and
		•		nonrecurring charges and adjustments included in ESOP valuation reports as prepared by an independent third party.
	To the extent included in net income or loss, the following items, without duplication, are deducted in determining Consolidated EBITDA:
		•		all cash payments on account of reserves, restructuring charges or other cash and non-cash charges added to net
		•		income pursuant to the list above in a previous period;
		•		any extraordinary gains; and
		•		all non-cash items of income.
	The Credit Agreement restricts us from doing any of the following without the prior consent of syndicate lenders that extended more than 50 percent of the aggregate amount of all Credit Agreement loans then outstanding:
		•		incur additional debt other than permitted additional debt;
		•		grant certain liens and security interests;
		•		enter into sale and leaseback transactions;
		•		make certain loans and investments including acquisitions of businesses, other than permitted acquisitions;
		•		consolidate, merge or sell all or substantially all our assets;
		•		pay dividends or distributions other than distributions required by the ESOP Plan or by certain legal requirements;
		•		make certain payments for subordinated indebtedness;
		•		enter into certain transactions with our shareholders and affiliates;
		•		enter into agreements which restrict our ability to incur liens or which restrict the ability of our subsidiaries to pay dividends
		•		change lines of business;
		•		repay subordinated debt before it is due;
		•		redeem or repurchase certain equity;
		•		enter into certain transactions not permitted under ERISA;
		•		change the terms of our other indebtedness or our KSOP in a way materially disadvantageous to us;
		•		make more than $8 million in capital expenditures in any fiscal year;
		•		pay certain earn-outs in connection with permitted acquisitions; or
		•		change our fiscal year.
	The Credit Agreement contains customary events of default including, without limitation:
		•		breach of representations and warranties;
		•		payment default;
		•		uncured covenant breaches;
		•		default under certain other debt exceeding an agreed amount;
		•		bankruptcy and certain insolvency events;
		•		incurrence of a civil or criminal liability in excess of $5 million of Alion or any subsidiary arising from a government investigation;
		•		unstayed judgments in excess of an agreed amount;
		•		failure of any Credit Agreement guarantee to be in effect;
		•		failure of the security interests to be valid, perfected, first priority security interests in the collateral;
		•		notice of debarment, suspension or termination under a material government contract;
		•		actual termination of a material contract due to alleged fraud, willful misconduct, negligence, default or any other wrongdoing;
		•		certain uncured defaults under our material contracts;
		•		certain ERISA violations;
		•		imposition on the ESOP Trust of certain taxes in excess of an agreed amount;
		•		final determination the ESOP is not a qualified plan;
		•		so long as any Secured Notes remain outstanding, the Intercreditor Agreement shall fail to be effective;
		•		a borrowing which would cause us to exceed a certain cash balance limit;
		•		failure to provide within 90 days of fiscal year-end, consolidated, comparative financial statements audited by an independent public accountant of recognized national standing with an opinion of such accountant that shall not include a “going concern” explanatory note or similar limitation, or
		•		a change of control (as defined below).
	Under the Credit Agreement a change of control generally occurs when, before Alion lists its common stock to trade on a national securities exchange and obtains at least $35 million in net proceeds from an underwritten public offering, the ESOP Trust fails to own at least 51 percent of Alion’s outstanding equity interests, or, after such a qualified public offering, any person or group other than the ESOP Trust owns more than 37.5 percent of Alion’s outstanding equity interests. A change of control may also occur if a majority of the seats (other than vacant seats) on Alion’s Board of Directors shall at any time be occupied by persons who were neither nominated by the board nor were appointed by directors so nominated. A change of control may also occur if a change of control occurs under any of Alion’s material debt including the Secured and Unsecured Note Indentures.
Alion depends heavily on federal government contracts. Delays in the federal budget process, reduced federal spending, budget cuts, sequestration, government shut downs and fiscal and political uncertainties have affected in the future could adversely affect Alion’s revenue in fiscal 2014. Despite uncertainties in the government contracting professional services marketplace, particularly the prospect of further sequestration-related effects and/or Department of Defense programmatic and budgetary cuts, management believes Alion will be able to generate sufficient revenue and EBITDA over the remaining life of the Credit Agreement to enable Alion to comply with Credit Agreement financial and non-financial covenants.
If Alion were unable to meet a Credit Agreement covenant because of a revenue shortfall or for any other reason, the Company could seek another covenant waiver or seek to negotiate a Credit Agreement amendment. Management can provide no assurance that Alion would be able to obtain a requested covenant waiver or amend the Credit Agreement on favorable terms.
Current Debt - Secured Notes
In March 2010, Alion issued and sold $310 million of its private units (Units) to Credit Suisse, which informed the Company it had resold most of the Units to qualified institutional buyers. Each of the 310,000 Units consisted of $1,000 in face value of Alion’s private 12% senior secured notes (Secured Notes) and a warrant to purchase 1.9439 shares of Alion common stock. On September 2, 2010, Alion exchanged the private Secured Notes for publicly tradable Secured Notes with the same terms.
Security. The Secured Notes are secured by a first priority security interest in all current and future tangible and intangible property of Alion and its guarantor subsidiaries, IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation. The Secured Notes are senior obligations of Alion and rank pari passu in right of payment with existing and future senior debt, including the Credit Agreement, except to the extent that the Intercreditor Agreement provides Credit Agreement lenders with a super priority right of payment with respect to the underlying collateral.
Guarantees. The Company’s obligations under the Secured Notes are guaranteed by the Company’s subsidiaries, IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation.
Interest and Fees. The Secured Notes bear interest at 12% per year; 10% is payable in cash and 2% increases the Secured Note principal (PIK Interest). Interest is payable semi-annually in arrears on May 1 and November 1. Alion pays interest to holders of record as of the immediately preceding April 15 and October 15. The Company must pay interest on overdue principal or interest at 13% per annum to the extent lawful. The Secured Notes mature November 1, 2014.
Covenants. As of December 31, 2013, Alion was in compliance with the covenants set forth in the Indenture governing its 12% Secured Notes (Secured Note Indenture). The Secured Note Indenture does not contain any financial covenants.
A Secured Note Indenture covenant restricts our ability to incur additional debt. Defined terms in the Secured Note Indenture include: Net Available Cash, Total Assets, Restricted Subsidiaries, Indebtedness, Adjusted EBITDA and Consolidated Interest Expense. Alion and its Restricted Subsidiaries may not issue, incur, assume, guarantee, or otherwise become liable for any debt unless our Adjusted EBITDA to Consolidated Interest Expense ratio is greater than 2.0 to 1.0. Adjusted EBITDA under the Secured Note Indenture differs from Consolidated EBITDA as defined in our Credit Agreement. Adjusted EBITDA is less than Consolidated EBITDA because it does not include employee investments in Alion common stock. Our Adjusted EBITDA to Consolidated Interest Expense ratio was 0.91 to 1.0 as of September 30, 2013 ($69.0 million in Adjusted EBITDA to $75.7 million in Consolidated Interest Expense). Our ratio was 0.89 to 1.0 as of December 31, 2013 ($67.7 million in Adjusted EBITDA to $75.7 million in Consolidated Interest Expense). Even if Adjusted EBITDA is not at least two times Consolidated Interest Expense, we may incur other permitted debt including:
	•		debt pursuant to certain agreements up to $25 million;
	•		permitted inter-company debt;
	•		the Secured Notes and any public notes exchanged for those notes;
	•		debt pre-dating the Secured Notes;
	•		permitted debt of acquired subsidiaries;
	•		permitted refinancing debt;
	•		hedging agreement debt;
	•		performance, bid, appeal and surety bonds and completion guarantees;
	•		ordinary course insufficient funds coverage;
	•		permitted refinancing debt guarantees;
	•		working capital debt of non-U.S. subsidiaries;
	•		debt for capital expenditures, and capital and synthetic leases up to $25 million in the aggregate and 2.5% of Alion’s Total Assets;
	•		permitted subordinated debt of Alion or any Restricted Subsidiary to finance a permitted acquisition, certain permitted ESOP transactions and refinancing debt of acquired non-U.S. subsidiaries up to $35 million in the aggregate;
	•		letter of credit reimbursement obligations;
	•		certain agreements in connection with a business disposition provided liabilities incurred in connection therewith do not exceed the cash and non-cash proceeds received and are not reflected on the Company’s balance sheet;
	•		certain deferred compensation agreements; and
	•		certain other debt up to $20 million.
The Secured Note Indenture has a covenant that restricts our ability to declare and pay any cash dividend or other distribution related to any equity interest in Alion, repurchase or redeem any equity interest of Alion, repurchase or redeem the Unsecured Notes or other subordinated debt, or make certain investments. However, within certain limits we may make such payments in limited amounts if Adjusted EBITDA is at least two times Consolidated Interest Expense. Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0, we may make or pay:
	•		such payments out of substantially concurrent contributions of equity and substantially concurrent incurrences of permitted debt;
	•		certain limited and permitted dividends;
	•		certain repurchases of the Company’s equity securities deemed to occur upon exercise of stock options or warrants;
	•		cash payments in lieu of the issuance of fractional shares in connection with the exercise of warrants, options or other securities convertible into or exchangeable for our equity securities;
	•		the required Secured Note premium payable on a change of control;
	•		certain permitted inter-company subordinated obligations;
	•		certain repurchases and redemptions of subordination obligations of the Company or a Subsidiary Guarantor from Net Available Cash (as defined in the Secured Note Indenture);
	•		repurchases of subordinated obligations in connection with an asset sale to the extent required by the Secured Note Indenture;
	•		certain permitted ESOP transactions;
	•		long-term incentive plan payments to our directors, officers and employees, subject to a $3 million annual cap that may increase annually;
	•		any purchase, repurchase, redemption, defeasance or other acquisition or retirement for value of the Unsecured Notes, up to an aggregate amount of $10 million; and
	•		certain other payments not exceeding $10 million in the aggregate.
The Secured Note Indenture restricts our ability to engage in other transactions including restricting our subsidiaries from making distributions and paying dividends to parents, merging or selling all or substantially all our assets, issuing certain subsidiary equity securities, engaging in certain transactions with affiliates, incurring liens, entering into sale lease-back transactions and engaging in business unrelated to our business when we issued the Secured Notes.
Events of Default. The Secured Note Indenture contains customary events of default, including:
	•		payment default on interest obligations when due;
	•		payment default on principal at maturity;
	•		uncured covenant breaches;
	•		default under an acceleration of certain other debt exceeding $30 million;
	•		bankruptcy and certain insolvency events;
	•		judgment for payment in excess of $30 million entered against the Company or any material subsidiary that remains outstanding for a period of 60 days and is not discharged, waived or stayed;
	•		failure of any Secured Note guarantee to be in effect or any subsidiary guarantor’s denial or disaffirmation of its guaranty obligations; and
	•		failure of any Secured Note security interest to constitute a valid and perfected lien with its applicable priority after a permitted cure period.
Change of Control. Upon a change in control, each Secured Note holder has the right to require Alion repurchase its notes in cash for 101% of principal plus accrued and unpaid interest. Any of the following events constitutes a change in control:
	•		subject to certain exceptions, a person, other than the ESOP Trust, is or becomes the beneficial owner, directly or indirectly, of more than 35% of the total voting power or voting stock of Alion;
	•		individuals who constituted Alion’s board of directors on March 22, 2010, (or individuals who were elected or nominated by them, or directors subsequently nominated or elected by them) cease for any reason to constitute a majority of the Company’s board of directors;
	•		the adoption of a plan relating to Alion’s liquidation or dissolution; and
	•		subject to certain exceptions, the merger or consolidation of the Company with or into another person or the merger of another person with or into the Company, or the sale of all or substantially all the assets of Alion to another person.
Optional Redemption. From April 1, 2013 through September 30, 2013, the Company was permitted to redeem all or a portion of the Secured Notes at 105% of principal, plus accrued and unpaid interest to the redemption date. From October 1, 2013 through March 31, 2014 the redemption price is 103% of principal, plus accrued and unpaid interest to the redemption date. After March 31, 2014, the Company is not required to pay a redemption premium.
Unsecured Notes
In February 2007, Alion issued and sold $250.0 million of its private 10.25% senior unsecured notes due February 1, 2015 (Unsecured Notes) to Credit Suisse, which informed the Company it had resold most of the notes to qualified institutional buyers. In June 2007, Alion exchanged the private Unsecured Notes for publicly tradable Unsecured Notes with the same terms. IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation guarantee the Unsecured Notes. From time to time, Alion has repurchased some of its outstanding Unsecured Notes in open market transactions. Through December 31, 2013, the Company had repurchased $15 million worth of Unsecured Notes: $2 million in November 2010; $3 million in June 2011, $5 million in June 2013 and an additional $5 million in July 2013. The Company recognized a gain on debt extinguishment for each Secured Note repurchase. In fiscal 2013, the Company recognized a $3.9 million gain; there were no debt extinguishments in fiscal 2012. In 2011, the Company recognized a $939 thousand debt extinguishment gain.
Interest and Fees. The Unsecured Notes bear interest at 10.25% per year, payable semi-annually in arrears on February 1 and August 1. Alion pays interest to holders of record as of the immediately preceding January 15 and July 15. The Company must pay interest on overdue principal or interest at 11.25% per annum to the extent lawful.
Covenants. There are no financial covenants in the Unsecured Note Indenture. As of December 31, 2013, we were in compliance with Unsecured Note Indenture non-financial covenants.
A covenant in the Unsecured Note Indenture restricts our ability to incur additional debt. Defined terms in the Unsecured Note Indenture include: Net Available Cash, Total Assets, Restricted Subsidiaries, Indebtedness, Adjusted EBITDA and Consolidated Interest Expense. Alion and its Restricted Subsidiaries may not issue, incur, assume, guarantee, or otherwise become liable for any indebtedness unless our Adjusted EBITDA to Consolidated Interest Expense ratio is
greater than 2.0 to 1.0. Adjusted EBITDA under the Unsecured Note Indenture differs from Consolidated EBITDA as defined in our Credit Agreement. Adjusted EBITDA is less than Consolidated EBITDA because it does not include employee investments in Alion common stock. Our Adjusted EBITDA to Consolidated Interest Expense ratio was 0.91 to 1.0 as of September 30, 2013 ($69.0 million in Adjusted EBITDA to $75.7 million in Consolidated Interest Expense). Our ratio was 0.89 to 1.0 as of December 31, 2013 ($67.7 million in Adjusted EBITDA to $75.7 million in Consolidated Interest Expense). Even if Adjusted EBITDA is not at least two times Consolidated Interest Expense, we may incur other permitted debt including:
	•		debt pursuant to our now terminated Term B Credit Facility and certain other contracts up to $360 million less principal repayments made under that indebtedness;
	•		permitted inter-company debt;
	•		the Unsecured Notes and any public notes exchanged for those notes;
	•		debt pre-dating the Unsecured Notes;
	•		permitted debt of acquired subsidiaries;
	•		permitted refinancing debt;
	•		hedging agreement debt;
	•		performance, bid, appeal and surety bonds and completion guarantees;
	•		ordinary course insufficient funds coverage;
	•		permitted refinancing debt guarantees;
	•		working capital debt of non-U.S. subsidiaries;
	•		debt for capital expenditures, capital and synthetic leases up to $25 million in the aggregate and 2.5% of Alion’s Total Assets;
	•		permitted subordinated debt of Alion or any Restricted Subsidiary to finance a permitted acquisition, certain permitted ESOP transactions and refinancing debt of acquired non-U.S. subsidiaries up to $35 million in the aggregate;
	•		letters of credit reimbursement obligations;
	•		certain agreements in connection with the disposition of a business provided liabilities incurred in connection therewith do not exceed the cash and non-cash proceeds received and are not reflected on the Company’s balance sheet;
	•		certain deferred compensation agreements; and
	•		certain other debt up to $35 million.
The Unsecured Note Indenture has a covenant that restricts our ability to declare and pay any cash dividend or other distribution with regard to any equity interest in the Company, make any repurchase or redemption of any equity interest in Alion, repurchase or redeem subordinated debt, and make certain investments. However, within certain limits we may make such payments in limited amounts if Adjusted EBITDA is at least two times Consolidated Interest Expense. Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0, we may make or pay:
	•		such payments out of substantially concurrent contributions of equity and substantially concurrent incurrences of permitted debt;
	•		certain limited and permitted dividends;
	•		certain repurchases of the Company’s equity securities deemed to occur upon exercise of stock options or warrants;
	•		cash payments in lieu of the issuance of fractional shares for the exercise of warrants, options or other securities convertible into or exchangeable for our equity securities;
	•		the required Unsecured Note premium payable on a change of control;
	•		certain permitted inter-company subordinated obligations;
	•		certain repurchases and redemptions of subordination obligations of the Company or a Subsidiary Guarantor from Net Available Cash;
	•		repurchases of subordinated obligations in connection with an asset sale to the extent required by the Indenture;
	•		repurchase of common stock from former Alion Joint Spectrum Center employees;
	•		certain permitted transactions with the ESOP not exceeding $25 million in the aggregate; and
	•		certain other payments not exceeding $30 million in the aggregate.
The Unsecured Note Indenture restricts the Company’s ability to engage in other transactions including restricting our subsidiaries from making distributions and paying dividends to parents, merging or selling all or substantially all our assets, issuing certain subsidiary equity securities, engaging in certain transactions with affiliates, incurring liens, entering into sale lease-back transactions and engaging in business unrelated to our business when we issued the Unsecured Notes.
Events of Default. The Unsecured Note Indenture contains customary events of default, including:
	•		payment default on interest obligations when due;
	•		payment default on principal at maturity;
	•		uncured covenant breaches;
	•		default under an acceleration of certain other debt exceeding $30 million;
	•		certain bankruptcy and insolvency events;
	•		judgment for payment in excess of $30 million entered against the Company or any material subsidiary that remains outstanding for a period of 60 days and is not discharged, waived or stayed; and
	•		failure of any Unsecured Note guarantee or any subsidiary guarantor’s denial or disaffirmation of its guaranty obligations.
Change of Control. Upon a change in control, each Unsecured Note holder has the right to require Alion repurchase its notes in cash for 101% of principal plus accrued and unpaid interest. Any of the following events constitutes a change in control:
	•		subject to certain exceptions, a person, other than the ESOP Trust, is or becomes the beneficial owner, directly or indirectly, of more than 35% of the total voting power or voting stock of Alion;
	•		individuals who constituted Alion’s board of directors on February 8, 2007, (or individuals who were elected or nominated by them, or individuals who were elected or nominated by them) cease for any reason to constitute a majority of the Company’s board of directors;
	•		adoption of a plan relating to Alion’s liquidation or dissolution; and
	•		subject to certain exceptions, Alion’s merger or consolidation with or into another person or the merger of another person with or into Alion, or the sale of all or substantially all our assets to another person.
Optional Redemption. We may redeem all or a portion of the Unsecured Notes at par plus accrued and unpaid interest to the redemption date. Alion needs to refinance some if not all its senior debt prior to maturity in November 2014 and February 2015 when the Company will have to payout more than $600 million over a three-month period. We are uncertain if the Company will be able to refinance these obligations or if refinancing terms will be favorable.
		December 31,		September 30,
		2013		2013
		(In thousands)
Secured Notes		$	5,551	$	13,741
Unsecured Notes			10,039		4,017
Total		$	15,590	$	17,758
As of December 31, 2013, Alion must make the following principal repayments (face value) for its outstanding debt. Unsecured Note face value exceeds carrying value and Secured Note face value exceeds carrying value. Carrying value includes debt issue costs which include the unamortized balances of: original issue discount; third-party debt issue expenses; and the initial fair value of common stock warrants issued in connection with the Secured Notes.
Future Payments by Fiscal Year:		2014		2015		Total
Secured Notes and PIK Interest(1)		$	—	$	339,788	$	339,788
Unsecured Notes(2)			—		235,000		235,000
Total Principal Payments		$	—	$	574,788	$	574,788
1	The Secured Notes due November 2014 include $310 million of debt issued in March 2010 and an estimated $29.8 million in PIK interest added to principal over the life of the notes. As of December 31, 2013, the $326.3 million carrying value on the face of the balance sheet included $310 million in principal, $23.1 million in PIK notes issued; $1.1 million in accrued PIK interest and is net of $7.9 million in aggregate unamortized debt issue costs. Initial debt issue costs consist of $7.7 million in original issue discount, $13.5 million in third-party costs and $20.8 million for the Secured Note warrants’ initial fair value.
2	As of December 31, 2013, the Unsecured Notes due February 2015 include $235 million in principal and approximately $1.0 million in unamortized debt issue costs (initially $7.1 million). Since issuing the Unsecured Notes, the Company has repurchased $15 million in principal.

Fair_Value_Measurement

Fair Value Measurement	3 Months Ended														12 Months Ended
	Dec. 31, 2013														Sep. 30, 2013
Fair Value Disclosures [Abstract]	'														'
Fair Value Measurement	'														'
	-11	Fair Value Measurement													(12) Fair Value Measurement
	Alion applies ASC 820 – Fair Value Measurements and Disclosures in determining the fair value to be disclosed for financial and nonfinancial assets and liabilities. The Company has no assets or liabilities, other than its redeemable common stock, which it is required to report at fair value. Valuation techniques utilized in the fair value measurement of assets and liabilities for each period presented were unchanged from prior practice.														Alion applies ASC 820 – Fair Value Measurements and Disclosures in determining the fair value to be disclosed for financial and nonfinancial assets and liabilities. The Company has no assets or liabilities, other than its redeemable common stock, which it is required to report at fair value. Valuation techniques utilized in the fair value measurement of assets and liabilities for each period presented were unchanged from prior practice.
	ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. It establishes a fair value hierarchy and a framework which requires categorizing assets and liabilities into one of three levels based on the assumptions (inputs) used in valuing the asset or liability. Level 1 provides the most reliable measure of fair value, while Level 3 generally requires significant management judgment. Level 1inputs are unadjusted, quoted market prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in inactive markets. Level 3 inputs include unobservable inputs that are supported by little, infrequent, or no market activity and reflect management’s own assumptions about inputs used in pricing the asset or liability. The Company uses the following valuation techniques to measure fair value.														ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in
	Level 1 primarily consists of financial instruments, such as overnight bank re-purchase agreements or money market mutual funds whose value is based on quoted market prices published by financial institutions, exchange funds, exchange-traded instruments and listed equities.														an orderly transaction between market participants at the measurement date. It establishes a fair value hierarchy and a framework which requires categorizing assets and liabilities into one of three levels based on the assumptions (inputs) used in valuing the asset or liability. Level 1 provides the most reliable measure of fair value, while Level 3 generally requires significant management judgment. Level 1inputs are unadjusted, quoted market prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in inactive markets. Level 3 inputs include unobservable inputs that are supported by little, infrequent, or no market activity and reflect management’s own assumptions about inputs used in pricing the asset or liability. The Company uses the following valuation techniques to measure fair value.
	Level 2 assets include U.S. Government and agency securities whose valuations are based on market prices from a variety of industry-standard data providers or pricing that considers various assumptions, including time value, yield curve, volatility factors, credit spreads, default rates, loss severity, current market and contractual prices for the underlying instruments, and broker and dealer quotes. All are observable in the market or can be derived principally from or corroborated by observable market data for which the Company can obtain independent external valuation information.														Level 1 primarily consists of financial instruments, such as overnight bank re-purchase agreements or money market mutual funds whose value is based on quoted market prices published by financial institutions, exchange funds, exchange-traded instruments and listed equities.
															Level 2 assets include U.S. Government and agency securities whose valuations are based on market prices from a variety of industry-standard data providers or pricing that considers various assumptions, including time value, yield curve, volatility factors, credit spreads, default rates, loss severity, current market and contractual prices for the underlying instruments, and broker and dealer quotes. All are observable in the market or can be derived principally from or corroborated by observable market data for which the Company can obtain independent external valuation information.
	Level 3 consists of unobservable inputs. Assets and liabilities are considered Level 3 when their fair value inputs are unobservable or not available, including situations involving limited market activity, where determination of fair value requires significant judgment or estimation.														Level 3 consists of unobservable inputs. Assets and liabilities are considered Level 3 when their fair value inputs are unobservable or not available, including situations involving limited market activity, where determination of fair value requires significant judgment or estimation.
	The table below sets out the face value, net carrying value and fair value of Alion’s Secured and Unsecured Notes. The fair values disclosed below are based on quoted market prices for Alion’s outstanding notes. This is a Level 2 measurement.
															The table below sets out the face value, net carrying value and fair value of Alion’s Secured and Unsecured Notes. The fair values disclosed below are based on quoted market prices for Alion’s outstanding notes. This is a Level 2 measurement.
			December 31, 2013						September 30, 2013
			(In thousands)													September 30, 2013						September 30, 2012
			Secured			Unsecured			Secured			Unsecured				(In thousands)
			Notes			Notes			Notes			Notes				Senior			Senior			Senior			Senior
	Face value of original notes outstanding		$	310,000		$	235,000		$	310,000		$	235,000			Secured			Unsecured			Secured			Unsecured
	PIK interest notes issued			23,086			—			19,788			—			Notes			Notes			Notes			Notes
															Face value of original notes outstanding	$	310,000		$	235,000		$	310,000		$	245,000
	Face value of outstanding notes		$	333,086		$	235,000		$	329,788		$	235,000		PIK interest notes issued		19,788			—			13,293			—
	PIK interest notes to be issued			1,111			—			2,748			—
															Face value of outstanding notes	$	329,788		$	235,000		$	323,293		$	245,000
	Face value of notes outstanding and notes to be issued		$	334,197		$	235,000		$	332,536		$	235,000		PIK interest notes to be issued		2,748			—			2,692			—
	Less: unamortized debt issue costs			(7,883	)		(962	)		(10,250	)		(1,168	)
															Face value of notes outstanding and notes to be issued	$	332,536		$	235,000		$	325,985		$	245,000
	Carrying value		$	326,314		$	234,038		$	322,286		$	233,832		Less: unamortized debt issue costs		(10,250	)		(1,168	)		(19,483	)		(2,077	)
															Carrying value	$	322,286		$	233,832		$	306,502		$	242,923
	Fair value of outstanding notes		$	339,681		$	165,894		$	335,295		$	151,928
															Fair value of outstanding notes	$	335,295		$	151,928		$	303,598		$	141,605

Secured_Note_Common_Stock_Warr

Secured Note Common Stock Warrants	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Text Block [Abstract]	'	'
Secured Note Common Stock Warrants	'	'
	(12) Secured Note Common Stock Warrants	(13) Secured Note Common Stock Warrants
	On March 22, 2010, Alion issued 310,000 Units consisting of $1,000 of Secured Note face value and a warrant to purchase 1.9439 shares of Alion common stock. The Secured Note warrants entitle holders to purchase a total of 602,614 shares of Alion common stock. Each Secured Note warrant has an exercise price of a penny per share; the Secured Note warrants are not redeemable for cash.	On March 22, 2010, Alion issued 310,000 Units consisting of $1,000 of Secured Note face value and a warrant to purchase 1.9439 shares of Alion common stock. The Secured Note warrants entitle holders to purchase a total of 602,614 shares of Alion common stock. Each Secured Note warrant has an exercise price of a penny per share; the Secured Note warrants are not redeemable for cash.
	The Company registered the Secured Notes, but is not required to register the warrants. The Units separated into Secured Notes and warrants on June 22, 2010. Each warrant became exercisable on March 22, 2011 and expires on March 15, 2017.	The Company registered the Secured Notes, but is not required to register the warrants. The Units separated into Secured Notes and warrants on June 22, 2010. Each warrant became exercisable on March 22, 2011 and expires on March 15, 2017.
	The Secured Note warrants had an initial fair value of approximately $20.8 million based on Alion’s former share price of $34.50. Alion recognized the value of the warrants as part of the debt issue costs for the Secured Notes and recorded a corresponding credit to equity. The Company accounts for the Secured Note warrants as equity and reassesses this classification each reporting period. The Company identified no required changes in accounting treatment as of December 31, 2013.	The Secured Note warrants had an initial fair value of approximately $20.8 million based on Alion’s former share price of $34.50. Alion recognized the value of the warrants as part of the debt issue costs for the Secured Notes and recorded a corresponding credit to equity. The Company accounts for the Secured Note warrants as equity and reassesses this classification each reporting period. The Company identified no required changes in accounting treatment as of September 30, 2013.

Leases

Leases	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Leases [Abstract]	'							'
Leases	'							'
	(13) Leases							(14) Leases
	Future minimum lease payments under non-cancelable operating leases for buildings, equipment and automobiles at December 31, 2013 are set out below. Alion subleases some excess capacity to subtenants under non-cancelable operating leases.							Future minimum lease payments under non-cancelable operating leases for buildings, equipment and automobiles at September 30, 2013 are set out below. Alion subleases some excess capacity to subtenants under non-cancelable operating leases.
	Lease Payments for Fiscal Years Ending	(In thousands)						Lease Payments for Fiscal Years Ending	(In thousands)
	2014 (for the remainder of fiscal year)	$	19,497					2014	$	26,009
	2015		25,076					2015		24,875
	2016		21,183					2016		21,041
	2017		17,783					2017		17,804
	2018		14,931					2018		14,931
	2019		6,162					And thereafter		19,109
	And thereafter		12,947
								Gross lease payments	$	123,769
	Gross lease payments	$	117,579					Less: non-cancelable subtenant receipts		(1,711	)
	Less: non-cancelable subtenant receipts		(1,593	)
								Net lease payments	$	122,058
	Net lease payments	$	115,986
	Composition of Total Rent Expense							Composition of Total Rent Expense
		Three Months Ended							September 30,
		December 31,							2013			2012			2011
		2013			2012				(In thousands)
		(In thousands)						Minimum rentals	$	21,530		$	20,639		$	21,992
	Minimum rentals	$	5,515		$	5,301		Less: Sublease rental income		(600	)		(156	)		(1,610	)
	Less: Sublease rental income		(143	)		(104	)
								Total rent expense, net	$	20,930		$	20,483		$	20,382
	Total rent expense, net	$	5,372		$	5,197

ESOP_Expense

ESOP Expense	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'
ESOP Expense	'	'
	(14) ESOP Expense	(16) ESOP Expense
	Alion makes 401(k) matching contributions in shares of its common stock. The Company matches the first 3% and one-half of the next 2% of eligible employee salary deferrals by contributing shares of Alion common stock to the ESOP Trust on March 31 and September 30 each year. The Company also makes profit sharing contributions of Alion common stock to the ESOP Trust on the same dates.	Alion makes 401(k) matching and profit sharing contributions in shares of its redeemable common stock. The Company matches the first 3% and one-half of the next 2% of eligible employee salary deferrals by contributing shares of Alion common stock to the ESOP Trust on March 31 and September 30 each year. The Company also makes profit sharing contributions of 2.5% of eligible employee compensation by contributing shares of Alion common stock to the ESOP Trust on the same dates.
	Based on the value of common stock contributed and to be contributed to the Plan, Alion recognized $3.6 million and $3.4 million in Plan expense for the three months ended December 31, 2013 and 2012.	Formerly, through June 2011, Alion profit sharing contributions consisted of 1% of eligible employee compensation in common stock issued to the ESOP Trust and 1.5% of eligible employee compensation in cash to the 401(k) component. Alion recognized $13.8 million, $13.8 million and $13.2 million in Plan expense for the years ended September 30, 2013, 2012 and 2011. In 2011, Plan expense included approximately $1.2 million in cash and approximately $11.0 million in common stock.
	In September 2013, Alion amended the ESOP to permit Alion to delay the Company’s contribution to the Plan for the six months ended September 30, 2013 and to delay transfer to the Company of employee contributions for investment in the ESOP component of the Plan. The Company made its September 30 contribution on the same schedule as it has done in the past. In December 2013, the ESOP Trust used employee funds to purchase approximately $930 thousand of Alion common stock at the September 30, 2013 price of $8.10 per share.	In September 2013, Alion amended the ESOP to delay the Company’s contribution to the Plan for the six months ended September 30, 2013 and to delay transfer to the Company of employee contributions for investment in the ESOP component of the Plan. The Company made its September 30 contribution on the same schedule as it has done in the past. In December 2013, the ESOP Trust used employee funds to purchase approximately $930 thousand of Alion common stock at the September 30, 2013 price of $8.10 per share.
	The non-cash component of ESOP expense appears in the statement of cash flows supplemental disclosures as “common stock issued in satisfaction of employer contribution liability.” It is included in operating cash flows from changes in accrued liabilities.	The non-cash component of ESOP expense appears in the statement of cash flows supplemental disclosures as “common stock issued in satisfaction of employer contribution liability.” It is included in operating cash flows from changes in accrued liabilities. The Company issued $13.8 million in redeemable common stock for the year ended September 30, 2013.

Long_Term_Incentive_Compensati

Long Term Incentive Compensation Plan	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Compensation Related Costs [Abstract]	'	'
Long Term Incentive Compensation Plan	'	'
	(15) Long Term Incentive Compensation Plan	(17) Long Term Incentive Plan
	Alion adopted a long-term cash incentive compensation plan for certain executives in December 2008. The Company amended its incentive compensation plan in January 2010 and amended and restated it in June 2013. The most recent amendment creates new change in control provisions that apply to future grants. Individual incentive compensation grants contain specific financial and performance goals and vest over varying periods. Some grants are for a fixed amount; others provide a range of values from a minimum of 50% to a maximum of 150% of initial grant value. The Company periodically evaluates the probability that individuals will achieve stated financial and performance goals.	Alion adopted a long-term cash incentive compensation plan for certain executives in December 2008. The Company amended its incentive compensation plan in January 2010 and amended and restated it in June 2013. The most recent amendment creates new change in control provisions that apply to future grants. Individual incentive compensation grants contain specific financial and performance goals and vest over varying periods. Some grants are for a fixed amount; others provide a range of values from a minimum of 50% to a maximum of 150% of initial grant value. The Company periodically evaluates the probability that individuals will achieve stated financial and performance goals.
	Alion recognizes long term incentive compensation expense based on outstanding grants’ stated values, estimated probability of achieving stated goals and estimated probable future grant values. The Company recognized $804 thousand and $742 thousand in incentive compensation expense for the quarters ended December 31, 2013 and 2012.	Alion recognizes long term incentive compensation expense based on outstanding grants’ stated values, estimated probability of achieving stated goals and estimated probable future grant values. The Company recognized $2.3 million, $1.4 million and $2.8 million in incentive compensation expense for the years ended September 30, 2013, 2012 and 2011.

Stock_Based_Compensation

Stock Based Compensation	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Text Block [Abstract]	'	'
Stock Based Compensation	'	'
	(16) Stock Based Compensation	(18) Stock-based Compensation
	Alion initially adopted its Stock Appreciation Rights (SAR) Plan in 2004. The Company amended and restated the SAR Plan in January 2007; amended it in January 2010; and amended and restated the SAR Plan in June 2013. The SAR Plan expires in November 2016. The most recent SAR Plan amendment revises certain change in control provisions.	Alion initially adopted its Stock Appreciation Rights (SAR) Plan in 2004. The Company amended and restated the SAR Plan in January 2007; amended it in January 2010; and amended and restated the SAR Plan in June 2013. The SAR Plan expires in November 2016. The most recent SAR Plan amendment revises certain change in control provisions.
	The chief executive officer may award SARs as he deems appropriate. Awards vest ratably over four years with payment following the grant date fifth anniversary. Grants with no intrinsic value expire on their year-five payment date. The SAR Plan permits accelerated vesting in the event of death, disability or a change in control of the Company. Approximately 587 thousand SARs were outstanding at December 31, 2013, at a weighted average grant date fair value of $22.52 per share. No outstanding grant has any intrinsic value.	The chief executive officer may award SARs as he deems appropriate. Awards vest ratably over four years with payment following the grant date fifth anniversary. Grants with no intrinsic value expire on their year-five payment date. The SAR Plan provides for accelerated vesting in the event of death or disability and provides for accelerated vesting of existing grants on a change in control. Approximately 709 thousand SARs were outstanding at September 30, 2013, at a weighted average grant date fair value of $24.96 per share. No outstanding grant has any intrinsic value. For the years ended September 30, 2013, 2012 and 2011, Alion recognized credits of $219 thousand, $90 thousand and $146 thousand in stock-based compensation expense for the SAR Plan. The Company has an aggregate SAR Plan liability of $26 thousand.
	In June 2013, the Company amended and restated its Phantom Stock Plan and its Performance Shares and Retention Phantom Stock Plan. No grants are outstanding under either of these plans.	Phantom Stock Plans
	Alion recognized no stock-based compensation expense for the three months ended December 31, 2013 and $10 thousand in stock based compensation expense for the three months ended December 31, 2012.	Alion formerly maintained Executive and Director Phantom Stock Plans. In 2011, Alion paid out the final vested Director Plan grant and recognized compensation expense of $4 thousand. In June 2013, the Company amended and restated its Phantom Stock Plan and its Performance Shares and Retention Phantom Stock Plan. No grants are outstanding under either of these plans.
	The Company uses a Black-Scholes-Merton option pricing model based on the fair market value of a share of its common stock to recognize stock –based compensation expense. There is no established public trading market for Alion’s common stock. The ESOP Trust owns all outstanding common stock. Alion does not expect to pay any dividends on its common stock and intends to retain future earnings, if any, for operating its business.	The Company uses a Black-Scholes-Merton option pricing model based on the fair market value of a share of its common stock to recognize stock –based compensation expense. There is no established public trading market for Alion’s common stock. The ESOP Trust owns all outstanding common stock. Alion does not expect to pay any dividends on its common stock and intends to retain future earnings, if any, for operating its business.

Income_Taxes

Income Taxes	3 Months Ended								12 Months Ended
	Dec. 31, 2013								Sep. 30, 2013
Income Tax Disclosure [Abstract]	'								'
Income Taxes	'								'
	-17	Income Taxes							(19) Income Taxes
	Deferred Taxes								Current Taxes
	Alion is subject to income taxes in the U.S., various states, India and Canada. Tax statutes and regulations within each jurisdiction are subject to interpretation requiring management to apply significant judgment. Alion recorded $1.7 million in goodwill-related deferred tax expense and liabilities for the three months ended December 31, 2013 and 2012. The Company recognized $2 thousand in current tax expense for its Indian subsidiary for the three months ended December 2013 and no current tax expense for the three months ended December 31, 2012.								Alion is subject to income taxes in the U.S., various states, Canada and India. Tax statutes and regulations within each jurisdiction are subject to interpretation requiring management to apply significant judgment. In 2013, the Company recognized approximately $2 thousand in current income tax expense for newly commenced business operations in India.
	The Company expects to be able to use existing and anticipated net operating losses (NOL) to offset taxes that may become due in the future if Alion has future taxable income. Even though Alion recorded a full valuation allowance for all deferred tax assets, the Company does not expect to pay any domestic income taxes for the foreseeable future and minimal foreign income taxes for its operations in India. Alion’s ability to utilize NOL tax benefits will depend upon how much future taxable income it has and may be limited under certain circumstances. Alion does not have any NOL tax benefits it can carry back to prior years.								Deferred Taxes
	The Company’s effective tax rate for the three months ended December 31, 2013 was -10.4% and -18.8% for the three months ended December 31, 2012. As of December 31, 2013 and September 30, 2013 the net deferred tax liability was:								Alion recorded approximately $7.0 million in deferred tax expense and liabilities related to tax-basis goodwill amortization in 2013, 2012 and 2011.
									Alion was formerly an S corporation and has been a C corporation since March 2010. The Company’s history of losses gives rise to a presumption that it might not be able to realize the full benefit of any deferred tax assets it is required to recognize. Therefore, Alion maintains a valuation allowance equal to the deferred tax assets it is required to recognize each reporting period and in total.
									The Company does not expect to pay any income taxes for the foreseeable future. Even though Alion has recorded a full valuation allowance for all deferred tax assets, management believes that if the Company were to become profitable, it should be able to use existing and anticipated net operating loss (NOL) carryforwards to offset taxes that might become due in the future. Alion’s ability to utilize NOL tax benefits will depend upon how much future taxable income it has and may be limited under certain circumstances. Alion does not have any NOL tax benefits it can carry back to years prior to becoming a C corporation.
			December 31,			September 30,
			2013			2013			The Company offers post-retirement prescription drug coverage to a limited number of retirees and beneficiaries. Alion has not claimed any federal tax credit in prior years. The Affordable Care Act has reduced the value of the federal subsidy for retiree drug coverage. Alion’s tax provision is unaffected by this legislative change. Management will decide whether to seek a subsidy in the future based on its anticipated value and the cost associated with seeking the subsidy.
			(In thousands)						Tax Uncertainties
	Current deferred tax asset		$	7,355		$	9,228		FASB Interpretation No. 48, “Accounting for Uncertainty in Income Taxes” now codified as ASC Topic 740 Income Taxes prescribes a recognition threshold and a measurement attribute for financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. The Company may recognize a benefit for that amount which it has a more than 50% chance of realizing. If the Company’s position involves uncertainty, then in order to recognize a benefit, a given tax position must be “more-likely-than-not” to be sustained upon examination by taxing authorities.
	Noncurrent deferred tax asset			98,007			87,812		Alion periodically assesses its liabilities and contingencies for all periods open to examination by tax authorities, based on the latest available information. Where management believes there is more than a 50 percent chance the Company’s tax position will not be sustained, Alion records its best estimate of the resulting tax liability, including interest. Interest or penalties related to income taxes are reported separately from income tax expense. The Company has analyzed its tax positions and has not recorded any liabilities for tax uncertainties.
	Valuation allowance			(105,362	)		(97,040	)	The Company has unrecorded tax benefits related to goodwill deductions. If Alion is able to utilize these benefits to reduce taxes payable in the future, it will recognize a reduction in its income tax liability and a corresponding reduction in goodwill carrying value.
	Noncurrent deferred tax liability			(59,873	)		(58,130	)	Alion may become subject to federal or state income tax examination for tax years ended September 2010 and after. Each of the Company’s open return year returns has given rise to an NOL carryforward including the Company’s 2010 return in which it elected not to defer the gain recognized on extinguishing certain former debt instruments. The Company does not expect resolution of tax matters for any open years to materially affect operating results, financial condition, cash flows or its effective tax rate.
									As of September 30, 2013 and 2012 deferred tax assets and related valuation allowances were $97.0 million and $78.4 million and deferred tax liabilities were $58.1 million and $51.2 million. Alion’s effective tax rate for fiscal years 2013, 2012 and 2011 was (23.6%), (20.2%) and (18.6%).
	Net deferred tax liability		$	(59,873	)	$	(58,130	)	The provision for income taxes for the years ended September 30, 2013, 2012 and 2011 was:
	Tax Uncertainties
	Based on the latest available information, Alion periodically assesses its liabilities and contingencies for all periods open to examination by tax authorities. Where management believes there is more than a 50 percent chance the Company’s tax position will not be sustained, Alion records its best estimate of the resulting tax liability, including interest. Interest or penalties related to income taxes are reported separately from income tax expense. The Company has analyzed its tax positions and has not recorded any liabilities for tax uncertainties.									Fiscal Years Ended
										September 30,
	Alion may become subject to federal or state income tax examination for tax years ended September 2010 and after. Alion’s former status as a pass-through entity owned by a tax-exempt trust makes an examination unlikely and the possibility of an adverse determination remote. The Company does not expect resolution of tax matters for any open years to materially affect its operating results, financial condition, cash flows or effective tax rate.									2013			2012			2011
										(In thousands)
									Current:
									Foreign		3			—			—
									Total current provision	$	3			—		$	—
									Deferred:
									Federal	$	5,740			5,740		$	5,740
									State		1,234			1,234			1,234
									Total deferred provision	$	6,974			6,974		$	6,974
									Total provision for income taxes	$	6,977			6,974		$	6,974
									Alion’s income tax provisions at September 30, 2013, 2012 and 2011 include the effects of state income taxes, debt extinguishment and changes in valuation allowances. The provision for income taxes for the years ended September 30, 2013, 2012 and 2011 differ from the amounts computed by applying the statutory U.S. federal income tax rate to income before taxes as a result of the following:
										Fiscal Years Ended September 30,
										2013						2012						2011
										(Dollars in thousands)
									Expected federal income tax (benefit)		35	%	$	(10,365	)		35	%	$	(12,066	)		35	%	$	(13,093	)
									State income taxes (net of federal benefit)		4.5	%		(1,325	)		4.5	%		(1,539	)		4.5	%		(1,666	)
									Nondeductible expenses		(0.4	%)		105			(0.4	%)		146			(0.6	%)		232
									Provision to return true-ups		(0.1	%)		15			(0.8	%)		286			(0.2	%)		84
									Tax credits		0.3	%		(79	)		0	%		—			0	%		—
									Changes in valuation allowance		(62.9	%)		18,626			(58.4	%)		20,147			(57.2	%)		21,417
									Income tax expense (benefit)		(23.6	%)	$	6,977			(20.2	%)	$	6,974			(18.6	%)	$	6,974
									At September 30, 2013 and 2012, the components of deferred tax assets and deferred tax liabilities were:
										September 30,
										2013			2012
										(In thousands)
									Deferred tax assets:
									Accrued expenses and reserves	$	9,228		$	11,206
									Intangible amortization		13,185			14,305
									Deferred rent		3,680			3,398
									Deferred wages		4,060			3,954
									Depreciation and leases		4,375			3,226
									Carryforwards and tax credits		62,487			42,300
									Other		25			25
									Gross deferred tax assets	$	97,040		$	78,414
									Less Valuation		(97,040	)		(78,414	)
									Deferred tax liabilities:
									Goodwill		(58,130	)		(51,156	)
									Net deferred tax asset/(liability)	$	(58,130	)	$	(51,156	)

Segment_Information

Segment Information	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Segment Reporting [Abstract]	'	'
Segment Information	'	'
	(18) Segment Information	(20) Segment Information and Customer Concentration
	Alion operates as a single segment, providing advanced engineering, information technology and operational solutions to strengthen national security and drive business results under contracts with the U.S. government, state and local governments, and commercial customers.	Alion operates as a single segment, providing advanced engineering, information technology and operational solutions to strengthen national security and drive business results under contracts with the U.S. government, state and local governments, and commercial customers.
	U.S. government customers typically exercise independent contracting authority. U.S. government agencies, department offices or divisions may use Alion’s services as a separate customer directly, or through a prime contractor, if they have independent decision-making and contracting authority within their organization. U.S. government prime contracts accounted for approximately 87% and 89% of total contract revenue for the three months ended December 31, 2013, and 2012.	U.S. government customers typically exercise independent contracting authority. U.S. government agencies, department offices or divisions may use Alion’s services as a separate customer directly, or through a prime contractor, if they have independent decision-making and contracting authority within their organization. U.S. government prime contracts accounted for approximately 89%, 86%, and 84% of total contract revenue for the years ended September 30, 2013, 2012 and 2011. The following five prime contracts represented over 50% of our revenue for the past three years.
				Fiscal Years Ended
				September 30,
		Government Agency	Contract	2013			2012			2011
		DoD—Defense Information Systems Agency	Weapons System Information Analysis Center for the Defense Information Systems Agency (ID/IQ contract vehicle)		27.6	%		17.1	%		8.2	%
		DoD—U.S. Navy	Seaport-E Multiple Award Contract for the Naval Sea Systems Command (ID/IQ contract vehicle)		20.7	%		20.1	%		13.5	%
		DoD—U.S. Air Force	Technical and Analytical Support for the U.S. Air Force		8.4	%		9.9	%		11.2	%
		DoD—U.S. Navy	Naval Sea Systems Command Surface Ships Life Cycle Program Management and Engineering Support		7.2	%		5.8	%		N/A
		DoD—Defense Information Systems Agency	Modeling and Simulation Information Analysis Center for the Defense Information Systems Agency (ID/IQ contract vehicle)		2.5	%		8.1	%		14.1	%

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'		'
Commitments and Contingencies	'		'
	-19	Commitments and Contingencies	(22) Commitments and Contingencies
	Government Audits		Government Audits
	Federal government cost-reimbursement contract revenues and expenses in the unaudited condensed consolidated financial statements are subject to DCAA audit and possible adjustment. Alion is a major contractor and DCAA maintains an office on site to perform various audits throughout the year. The Company has settled indirect rates through 2005 based on completed DCAA audits. All subsequent years are open. We are disputing the government’s claim for penalties and interest for 2005. It is our position that the statute of limitations has expired on any government contractual claims, including any claims for penalties and interest, on our 2005 indirect rate proposal. Alion has recorded federal government contract revenue based on amounts it expects to realize upon final settlement.		Federal government cost-reimbursement contract revenues and expenses in the audited consolidated financial statements are subject to DCAA audit and possible adjustment. Alion is a major contractor and DCAA maintains an office on site to perform various audits throughout the year. The Company has settled indirect rates through 2005 based on completed DCAA audits. All subsequent years are open. Alion has recorded federal government contract revenue based on amounts it expects to realize upon final settlement.
	Legal Proceedings		Legal Proceedings
	We are involved in routine legal proceedings occurring in the ordinary course of business that we believe are not material to our financial condition, operating results, or cash flows. As a government contractor, from time to time we may be subject to DCAA audits and federal government inquiries. The federal government may suspend or debar for a period of time any federal contractor it finds has violated the False Claims Act, and any contractor indicted or convicted of violations of other federal laws. The federal government could also impose fines or penalties.		We are involved in routine legal proceedings occurring in the ordinary course of business that we believe are not material to our financial condition, operating results, or cash flows. As a government contractor, from time to time we may be subject to DCAA audits and federal government inquiries. The federal government may suspend or debar for a period of time any federal contractor it finds has violated the False Claims Act, and any contractor indicted or convicted of violations of other federal laws. The federal government could also impose fines or penalties.
	Alion depends on federal government contracts; suspension or debarment could have a material, adverse effect on our business, financial condition, operating results, cash flows and our ability to meet our financial obligations. We are not aware of any such pending federal government claims or investigations.		Alion depends on federal government contracts; suspension or debarment could have a material, adverse effect on our business, financial condition, operating results, cash flows and our ability to meet our financial obligations. We are not aware of any such pending federal government claims or investigations.

GuarantorNonGuarantor_Unaudite

Guarantor/Non-Guarantor Unaudited Condensed Consolidated Financial Information	3 Months Ended																	12 Months Ended
	Dec. 31, 2013																	Sep. 30, 2013
Text Block [Abstract]	'																	'
Guarantor/Non-Guarantor Unaudited Condensed Consolidated Financial Information	'																	'
	-20	Guarantor/Non-guarantor Unaudited Condensed Consolidated Financial Information																(21) Guarantor/Non-guarantor Condensed Consolidated Financial Information
	Certain of Alion’s 100% owned domestic subsidiaries have jointly, severally, fully and unconditionally guaranteed both the Secured Notes and the Unsecured Notes which are general obligations of the Company. In March 2010, the Unsecured Note Indenture was amended to include as Unsecured Note guarantors all subsidiaries serving as Secured Note guarantors.																	Certain of Alion’s 100% owned domestic subsidiaries have jointly, severally, fully and unconditionally guaranteed both the Secured Notes and the Unsecured Notes which are general obligations of the Company. In March 2010, the Unsecured Note Indenture was amended to include as Unsecured Note guarantors all subsidiaries serving as Secured Note guarantors.
	The following information presents unaudited condensed consolidating balance sheets as of December 31, 2013 and September 30, 2013; unaudited condensed consolidating statements of operations and comprehensive loss for the three month period ended December 31, 2013 and 2012; and unaudited condensed consolidating statements of cash flows for the three months ended December 31, 2013 and 2012 of Alion, its guarantor subsidiaries and its non-guarantor subsidiaries. Investments include Alion’s investments in its subsidiaries presented using the equity method of accounting.																	The following information presents condensed consolidating balance sheets as of September 30, 2013 and September 30, 2012; condensed consolidating statements of operations and comprehensive loss and cash flows for the years ended September 30, 2013, 2012 and 2011 of Alion, its guarantor subsidiaries and its non-guarantor subsidiaries. Investments include Alion’s investments in its subsidiaries presented using the equity method of accounting.
	Condensed Consolidating Balance Sheet as of December 31, 2013 (unaudited)																	Condensed Consolidating Balance Sheet Information at September 30, 2013
			Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
						Companies			Guarantor													Companies			Companies
									Companies										(In thousands)
			(In thousands)															Current assets:
	Current assets:																	Cash and cash equivalents	$	25,617		$	(24	)	$	20		$	—		$	25,613
	Cash and cash equivalents		$	4,670		$	(10	)	$	27		$	—		$	4,687		Accounts receivable, net		169,304			2,735			565			—			172,604
	Accounts receivable, net			166,283			2,038			642			—			168,963		Receivable due from ESOP Trust		930			—			—			—			930
	Prepaid expenses and other current assets			5,587			36			25			—			5,648		Prepaid expenses and other current assets		4,449			188			(154	)		—			4,483
	Total current assets			176,540			2,064			694			—			179,298		Total current assets		200,300			2,899			431			—			203,630
	Property, plant and equipment, net			8,552			515			3			—			9,070		Property, plant and equipment, net		9,139			525			4			—			9,668
	Intangible assets, net			1,735			—			—			—			1,735		Intangible assets, net		2,040			—			—			—			2,040
	Goodwill			398,921			—			—			—			398,921		Goodwill		398,921			—			—			—			398,921
	Investment in subsidiaries			28,710			—			—			(28,710	)		—		Investment in subsidiaries		28,420			—			—			(28,420	)		—
	Intercompany receivables			1,963			28,536			—			(30,499	)		—		Intercompany receivables		1,906			27,828			—			(29,734	)		—
	Other assets			10,364			—			4			—			10,368		Other assets		10,363			—			4			—			10,367
	Total assets		$	626,785		$	31,115		$	701		$	(59,209	)	$	599,392		Total assets	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
	Current liabilities:																	Current liabilities:
	Interest payable		$	15,590		$	—		$	—		$	—		$	15,590		Interest payable	$	17,758		$	—		$	—		$	—		$	17,758
	Secured notes			326,313			—			—			—			326,313		Trade accounts payable		61,563			58			1			—			61,622
	Trade accounts payable			59,465			40			31			—			59,536		Accrued liabilities		39,169			144			80			—			39,393
	Accrued liabilities			36,710			96			103			—			36,909		Accrued payroll and related liabilities		37,404			517			33			—			37,954
	Accrued payroll and related liabilities			31,399			303			31			—			31,733		Billings in excess of costs revenue earned		4,250			84			—			—			4,334
	Billings in excess of revenue earned			4,452			110			—			—			4,562
																		Total current liabilities		160,144			803			114			—			161,061
	Total current liabilities			473,929			549			165			—			474,643		Intercompany payables		27,826			153			1,754			(29,733	)		—
	Intercompany payables			28,537			—			1,962			(30,499	)		—		Secured Notes		322,286			—			—			—			322,286
	Unsecured notes			234,038			—			—			—			234,038		Unsecured Notes		233,832			—			—			—			233,832
	Accrued compensation and benefits, excluding current portion			5,998			—			—			—			5,998		Accrued compensation and benefits, excluding current portion		5,736			—			—			—			5,736
	Non-current portion of lease obligations			12,110			430			—			—			12,540		Non-current portion of lease obligations		12,374			447			—			—			12,821
	Deferred income taxes			59,873			—			—			—			59,873		Deferred income taxes		58,130			—			—			—			58,130
	Commitments and contingencies																	Commitments and contingencies		—			—			—			—			—
	Redeemable common stock			61,896			—			—			—			61,896		Redeemable common stock		61,895			—			—			—			61,895
	Common stock warrants			20,785			—			—			—			20,785		Common stock warrants		20,785			—			—			—			20,785
	Common stock of subsidiaries			—			4,084			9			(4,093	)		—		Common stock of subsidiaries		—			4,084			9			(4,093	)		—
	Accumulated other comprehensive loss			130			—			—			—			130		Accumulated other comprehensive loss		130			—			—			—			130
	Accumulated deficit			(270,511	)		26,052			(1,435	)		(24,617	)		(270,511	)	Accumulated surplus (deficit)		(252,049	)		25,765			(1,438	)		(24,328	)		(252,050	)
	Total liabilities, redeemable common stock and accumulated deficit		$	626,785		$	31,115		$	701		$	(59,209	)	$	599,392		Total liabilities, redeemable common stock and stockholder’s deficit	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
	Condensed Consolidating Balance Sheet as of September 30, 2013 (unaudited)																	Condensed Consolidating Balance Sheet Information at September 30, 2012
			Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
									Guarantor													Companies			Companies
									Companies										(In thousands)
			(In thousands)															Current assets:
	Current assets:																	Cash and cash equivalents	$	27,271		$	(44	)	$	—		$	—		$	27,227
	Cash and cash equivalents		$	25,617		$	(24	)	$	20		$	—		$	25,613		Accounts receivable, net		172,365			2,783			145			—			175,293
	Accounts receivable, net			169,304			2,735			565			—			172,604		Receivable due from ESOP Trust		1,129			—			—			—			1,129
	Receivable due from ESOP Trust			930			—			—			—			930		Prepaid expenses and other current assets		5,378			70			—			—			5,448
	Prepaid expenses and other current assets			4,449			188			(154	)		—			4,483
																		Total current assets		206,143			2,809			145			—			209,097
	Total current assets			200,300			2,899			431			—			203,630		Property, plant and equipment, net		10,064			529			12			—			10,605
	Property, plant and equipment, net			9,139			525			4			—			9,668		Intangible assets, net		5,242			—			—			—			5,242
	Intangible assets, net			2,040			—			—			—			2,040		Goodwill		398,921			—			—			—			398,921
	Goodwill			398,921			—			—			—			398,921		Investment in subsidiaries		27,994			—			—			(27,994	)		—
	Investment in subsidiaries			28,420			—			—			(28,420	)		—		Intercompany receivables		1,438			27,475			—			(28,913	)		—
	Intercompany receivables			1,906			27,828			—			(29,734	)		—		Other assets		11,427			—			4			—			11,431
	Other assets			10,363			—			4			—			10,367
																		Total assets	$	661,229		$	30,813		$	161		$	(56,907	)	$	635,296
	Total assets		$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
																		Current liabilities:
	Current liabilities:																	Interest payable	$	17,658		$	—		$	—		$	—		$	17,658
Interest payable		$	17,758		$	—		$	—		$	—		$	17,758		Trade accounts payable		44,582			201			10			—			44,793
Trade accounts payable			61,563			58			1			—			61,622		Accrued liabilities		52,265			190			5			—			52,460
Accrued liabilities			39,169			144			80			—			39,393		Accrued payroll and related liabilities		39,305			589			32			—			39,926
Accrued payroll and related liabilities			37,404			517			33			—			37,954		Billings in excess of costs revenue earned		2,656			6			4			—			2,666
Billings in excess of costs revenue earned			4,250			84			—			—			4,334
																	Total current liabilities		156,466			986			51			—			157,503
Total current liabilities			160,144			803			114			—			161,061		Intercompany payables		27,476			—			1,437			(28,913	)		—
Intercompany payables			27,826			153			1,754			(29,733	)		—		Secured Notes		306,502			—			—			—			306,502
Secured Notes			322,286			—			—			—			322,286		Unsecured Notes		242,923			—			—			—			242,923
Unsecured Notes			233,832			—			—			—			233,832		Accrued compensation and benefits, excluding current portion		5,905			—			—			—			5,905
Accrued compensation and benefits, excluding current portion			5,736			—			—			—			5,736		Non-current portion of lease obligations		11,858			506			—			—			12,364
Non-current portion of lease obligations			12,374			447			—			—			12,821		Deferred income taxes		51,156			—			—			—			51,156
Deferred income taxes			58,130			—			—			—			58,130		Commitments and contingencies
Redeemable common stock			61,895			—			—			—			61,895		Redeemable common stock		110,740			—			—			—			110,740
Common stock of subsidiaries			—			4,084			9			(4,093	)		—		Common stock warrants		20,785			—			—			—			20,785
Commitments and contingencies																	Common stock of subsidiaries		—			4,084			—			(4,084	)		—
Common stock warrants			20,785			—			—			—			20,785		Accumulated other comprehensive loss		(149	)		—			—			—			(149	)
Accumulated other comprehensive loss			130			—			—			—			130		Accumulated surplus (deficit)		(272,433	)		25,237			(1,327	)		(23,910	)		(272,433	)
Accumulated surplus (deficit)			(252,049	)		25,765			(1,438	)		(24,328	)		(252,050	)
																	Total liabilities, redeemable common stock and stockholder’s deficit	$	661,229		$	30,813		$	161		$	(56,907	)	$	635,296
Total liabilities, redeemable common stock and accumulated deficit		$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
																	Condensed Consolidating Statement of Comprehensive Loss
Condensed Consolidating Statement of Operations and Comprehensive Loss for the Three Months Ended December 31, 2013 (unaudited)
																		Year Ended September 30, 2013
		Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
					Companies			Guarantor													Companies			Companies
								Companies										(In thousands)
		(In thousands)															Contract revenue	$	839,608		$	8,627		$	737		$	—		$	848,972
Contract revenue		$	183,384			1,771			225			—		$	185,380		Direct contract expenses		663,380			5,638			486			—			669,504
Direct contract expense			144,060			1,091			124			—			145,275
																	Gross profit		176,228			2,989			251			—			179,468
Gross profit			39,324			680			101			—			40,105
																	Operating expenses		81,838			1,972			318			—			84,128
Operating expenses			18,385			392			87						18,864		General and administrative		52,491			604			44			—			53,139
General and administrative			18,983			1			9			—			18,993
																	Operating income (loss)		41,899			413			(111	)		—			42,201
Operating income			1,956			287			5			—			2,248		Other income (expense):
Other income (expense):																	Interest income		55			—			—			—			55
Interest income			11			—			—			—			11		Interest expense		(75,700	)		—			—			—			(75,700	)
Interest expense			(18,948	)		—			—			—			(18,948	)	Other		(200	)		116			—			—			(84	)
Other			(28	)					—			—			(28	)	Gain on debt extinguishment		3,913			—			—			—			3,913
Equity in net income (loss) of subsidiaries			292						—			(292	)		—		Equity in net income (loss) of subsidiaries		418			—			—			(418	)		—
Total other expenses			(18,673	)		—			—			(292	)		(18,965	)	Total other income (expense)		(71,514	)		116			—			(418	)		(71,816	)
																	Income (loss) before taxes		(29,615	)		529			(111	)		(418	)		(29,615	)
(Loss) income before taxes			(16,717	)		287			5			(292	)		(16,717	)	Income tax expense		(6,977	)		—			—			—			(6,977	)
Income tax expense			(1,745	)		—			—			—			(1,745	)
																	Net income (loss)	$	(36,592	)	$	529		$	(111	)	$	(418	)	$	(36,592	)
Net loss		$	(18,462	)	$	287		$	5		$	(292	)	$	(18,462	)
																	Other comprehensive income:
Other comprehensive income																	Postretirement actuarial gains		279			—			—			—			279
Postretirement actuarial gains			—			—			—			—			—
																	Comprehensive income (loss)	$	(36,313	)		529			(111	)		(418	)		(36,313	)
Comprehensive income (loss)		$	(18,462	)	$	287		$	5		$	(292	)	$	(18,462	)
																	Condensed Consolidating Statement of Comprehensive Loss
Condensed Consolidating Statement of Operations and Comprehensive Loss for the Three Months Ended December 31, 2012 (unaudited)
																		Year Ended September 30, 2012
																		Parent			Guarantor			Non-			Eliminations			Consolidated
		Parent			Guarantor			Non-			Eliminations			Consolidated							Companies			Guarantor
					Companies			Guarantor																Companies
								Companies										(In thousands)
		(In thousands)															Contract revenue	$	802,664		$	14,015		$	525		$	—		$	817,204
Contract revenue		$	202,057		$	2,218		$	54		$	—		$	204,329		Direct contract expenses		624,788			7,743			300			—			632,831
Direct contract expense			159,162			1,337			136			—			160,635
																	Gross profit		177,876			6,272			225			—			184,373
Gross profit			42,895			881			(82	)		—			43,694
																	Operating expenses		88,736			2,531			227			—			91,494
Operating expenses			21,621			560			69			—			22,250		General and administrative		52,123			156			162			—			52,441
General and administrative			11,734			49			21			—			11,804
																	Operating income (loss)		37,017			3,585			(164	)		—			40,438
Operating income (loss)			9,540			272			(172	)		—			9,640		Other income (expense):
Other income (expense):																	Interest income		78			—			—			—			78
Interest income			17			—			—			—			17		Interest expense		(74,934	)		—			—			—			(74,934	)
Interest expense			(18,919	)		—			—			—			(18,919	)	Other		(63	)		9			(1	)		—			(55	)
Other			(15	)		—			—			—			(15	)	Equity in net income (loss) of subsidiaries		3,429			—			—			(3,429	)		—
Equity in net income of subsidiaries			100			—			—			(100	)		—
																	Total other income (expense)		(71,490	)		9			(1	)		(3,429	)		(74,911	)
Total other (expense) income			(18,817	)		—			—			(100	)		(18,917	)	Income (loss) before taxes		(34,473	)		3,594			(165	)		(3,429	)		(34,473	)
																	Income tax expense		(6,974	)		—			—			—			(6,974	)
(Loss) income before taxes			(9,277	)		272			(172	)		(100	)		(9,277	)
Income tax expense			(1,744	)		—			—			—			(1,744	)	Net income (loss)	$	(41,447	)	$	3,594		$	(165	)	$	(3,429	)	$	(41,447	)
Net income (loss)		$	(11,021	)	$	272		$	(172	)	$	(100	)	$	(11,021	)	Other comprehensive income:
																	Postretirement actuarial gains		26			—			—			—			26
Other comprehensive income:
Postretirement actuarial gains			—			—			—			—			—		Comprehensive income (loss)	$	(41,421	)		3,594			(165	)		(3,429	)		(41,421	)
Comprehensive income (loss)		$	(11,021	)	$	272		$	(172	)	$	(100	)	$	(11,021	)	Condensed Consolidating Statement of Comprehensive Loss
Condensed Consolidating Statement of Cash Flows for the Three Months Ended December 31, 2013 (unaudited)																		Year Ended September 30, 2011
																		Parent			Guarantor			Non-			Eliminations			Consolidated
																					Companies			Guarantor
		Parent			Guarantor			Non-			Consolidated													Companies
					Companies			Guarantor										(In thousands)
								Companies									Contract revenue	$	769,467		$	17,025		$	822		$	—		$	787,314
		(In thousands)															Direct contract expenses		593,600			9,333			548			—			603,481
Net cash (used in) provided by operating activities		$	(19,934	)	$	24		$	7		$	(19,903	)
																	Gross profit		175,867			7,692			274			—			183,833
Cash flows from investing activities:
Capital expenditures			(263	)		(10	)		—			(273	)				Operating expenses		79,871			3,076			88			—			83,035
																	General and administrative		64,374			620			311			—			65,305
Net cash used in investing activities			(263	)		(10	)		—			(273	)
Cash flows from financing activities:																	Operating income (loss)		31,622			3,996			(125	)		—			35,493
Payment of debt issue costs			(750	)		—			—			(750	)				Other income (expense):
Revolver borrowings			10,000			—			—			10,000					Interest income		45			—			—			—			45
Revolver payments			(10,000	)		—			—			(10,000	)				Interest expense		(73,919	)		—			—			—			(73,919	)
Redeemable common stock purchased from ESOP Trust			(934	)		—			—			(934	)				Other		(535	)		568			(1	)		—			32
Redeemable common stock sold to ESOP Trust			934			—			—			934					Gain on debt extinguishment		939			—			—			—			939
																	Equity in net income (loss) of subsidiaries		4,438			—			—			(4,438	)		—
Net cash used in financing activities			(750	)		—			—			(750	)
Net (decrease) increase in cash and cash equivalents			(20,947	)		14			7			(20,926	)				Total other income (expense)		(69,032	)		568			(1	)		(4,438	)		(72,903	)
Cash and cash equivalents at beginning of period			25,617			(24	)		20			25,613					Income (loss) before taxes		(37,410	)		4,564			(126	)		(4,438	)		(37,410	)
																	Income tax expense		(6,974	)		—			—			—			(6,974	)
Cash and cash equivalents at end of period		$	4,670		$	(10	)	$	27		$	4,687
																	Net income (loss)	$	(44,384	)	$	4,564		$	(126	)	$	(4,438	)	$	(44,384	)
Condensed Consolidating Statement of Cash Flows for the Three Months Ended December 31, 2012 (unaudited)																	Other comprehensive income:
																	Post retirement actuarial gains		55			—			—			—			55
		Parent			Guarantor			Non-			Consolidated						Comprehensive income (loss)		(44,329	)		4,564			(126	)		(4,438	)		(44,329	)
					Companies			Guarantor
								Companies									Condensed Consolidating Statement of Cash Flows
		(In thousands)															Year Ended September 30, 2013
Net cash (used in) provided by operating activities		$	(6,337	)	$	15		$	5		$	(6,317	)
Cash flows from investing activities:																		Parent			Guarantors			Non-			Consolidated
Capital expenditures			(603	)		—			—			(603	)											Guarantors
																		(In thousands)
Net cash used in investing activities			(603	)		—			—			(603	)				Net cash provided by operating activities	$	10,666		$	97		$	20		$	10,783
Cash flows from financing activities:																	Cash flows from investing activities:
Redeemable common stock purchased from ESOP Trust			(1,975	)		—			—			(1,975	)				Capital expenditures		(1,792	)		(77	)		—			(1,869	)
Net cash provided by financing activities			(846	)		—			—			(846	)				Net cash provided by (used in) investing activities		(1,792	)		(77	)		—			(1,869	)
Net increase (decrease) in cash and cash equivalents			(7,786	)		15			5			(7,766	)				Cash flows from financing activities:
Cash and cash equivalents at beginning of period			27,271			(44	)		—			27,227					Repurchase of Unsecured Notes		(6,030	)		—			—			(6,030	)
																	Revolver borrowings		16,461			—			—			16,461
Cash and cash equivalents at end of period		$	19,485		$	(29	)	$	5		$	19,461					Revolver repayments		(16,461	)		—			—			(16,461	)
																	Loan to ESOP Trust		(1,907	)		—			—			(1,907	)
																	ESOP loan repayment		1,907			—			—			1,907
																	Redeemable common stock purchased from ESOP Trust		(6,664	)		—			—			(6,664	)
																	Redeemable common stock sold to ESOP Trust		2,166			—			—			2,166
																	Net cash used in financing activities		(10,528	)		—			—			(10,528	)
																	Net increase (decrease) in cash and cash equivalents		(1,654	)		20			20			(1,614	)
																	Cash and cash equivalents at beginning of period		27,271			(44	)		—			27,227
																	Cash and cash equivalents at end of period	$	25,617		$	(24	)	$	20		$	25,613
																	Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2012
																		Parent			Guarantors			Non-			Consolidated
																								Guarantors
																		(In thousands)
																	Net cash provided by (used in) operating activities	$	12,700		$	(19	)	$	—		$	12,681
																	Cash flows from investing activities:
																	Capital expenditures		(2,733	)		2			—			(2,731	)
																	Net cash provided by (used in) investing activities		(2,733	)		2			—			(2,731	)
																	Cash flows from financing activities:
																	Revolver borrowings		26,000			—			—			26,000
																	Revolver repayments		(26,000	)		—			—			(26,000	)
																	Loan to ESOP Trust		(477	)		—			—			(477	)
																	ESOP loan repayment		477			—			—			477
																	Redeemable common stock purchased from ESOP Trust		(4,843	)		—			—			(4,843	)
																	Redeemable common stock sold to ESOP Trust		1,302			—			—			1,302
																	Net cash used in financing activities		(3,541	)		—			—			(3,541	)
																	Net increase (decrease) in cash and cash equivalents		6,426			(17	)		—			6,409
																	Cash and cash equivalents at beginning of period		20,845			(27	)		—			20,818
																	Cash and cash equivalents at end of period	$	27,271		$	(44	)	$	—		$	27,227
																	Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2011
																		Parent			Guarantors			Non-			Consolidated
																								Guarantors
																		(In thousands)
																	Net cash provided by operating activities	$	5,061		$	636		$	24		$	5,721
																	Cash flows from investing activities:
																	Capital expenditures		(5,694	)		(588	)		(23	)		(6,305	)
																	Proceeds from sale of fixed assets		14			—			—			14
																	Net cash used in investing activities		(5,680	)		(588	)		(23	)		(6,291	)
																	Cash flows from financing activities:
																	Payment of debt issuance cost		(710	)		—			—			(710	)
																	Repurchase unsecured notes		(3,993	)		—			—			(3,993	)
																	Revolver borrowings		17,000			—			—			17,000
																	Revolver payments		(17,000	)		—			—			(17,000	)
																	Loan to ESOP Trust		(776	)		—			—			(776	)
																	ESOP loan repayment		776			—			—			776
																	Redeemable common stock purchased from ESOP Trust		(5,762	)		—			—			(5,762	)
																	Redeemable common stock sold to ESOP Trust		5,158			—			—			5,158
																	Net cash used in financing activities		(5,307	)		—			—			(5,307	)
																	Net increase (decrease) in cash and cash equivalents		(5,926	)		48			1			(5,877	)
																	Cash and cash equivalents at beginning of period		26,770			(74	)		(1	)		26,695
																	Cash and cash equivalents at end of period	$	20,844		$	(26	)	$	—		$	20,818

Subsequent_Event

Subsequent Event	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Subsequent Events [Abstract]	'		'
Subsequent Event	'		'
	-21	Subsequent Event	(24) Subsequent Events
	In January 2014, the Board of Directors authorized the Company to file a registration statement on Form S-1 with the U.S. Securities and Exchange Commission to register the offer to exchange Unsecured Notes for, at the holders’ option, either (a) new third lien notes of equivalent face value, with a combination of interest payable in cash and in kind, and new warrants to purchase up to 27.5% of the Company’s common stock or (b) a limited amount of cash at a price below par plus accrued and unpaid interest and a 1.5% early tender cash payment, if applicable. The registration statement also registers the offer of new third lien notes and warrants to holders of Unsecured Notes who tender their Unsecured Notes in the exchange offer and meet certain other conditions.		Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of a potential covenant breach, resulting from an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this covenant. The Company paid no fee for this waiver.
			Also in December 2013, the Company sold approximately $934 thousand worth of its common stock to the ESOP Trust. The Company offered and sold the securities to the ESOP Trust pursuant to an exemption from registration under Section 4(2) of the Securities Act of 1933, as amended.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Accounting Policies [Abstract]	'	'
Basis of Presentation and Principles of Consolidation	'	'
	Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation
	The accompanying unaudited condensed consolidated financial statements include the accounts of Alion Science and Technology Corporation (a Delaware corporation), and its wholly-owned subsidiaries and have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission. Certain information and note disclosures normally included in the annual financial statements, prepared in accordance with generally accepted accounting principles in the United States of America (GAAP), have been omitted pursuant to those rules and regulations. However, the Company believes that the disclosures made are adequate to make the information presented not misleading. The statements are prepared on the accrual basis of accounting and include the accounts of Alion and its wholly-owned subsidiaries from their date of acquisition or formation. All inter-company accounts have been eliminated in consolidation. There have been no changes to Alion’s subsidiaries in the current fiscal year.	The accompanying audited consolidated financial statements include the accounts of Alion Science and Technology Corporation (a Delaware corporation) and its wholly-owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles on the accrual basis of accounting. The statements include the accounts of Alion and its wholly-owned subsidiaries from date of formation or acquisition. All inter-company accounts have been eliminated in consolidation. The wholly-owned subsidiaries are:
	In management’s opinion, the accompanying unaudited condensed consolidated financial statements reflect all adjustments consisting of normal recurring adjustments and reclassifications that are necessary for fair presentation of the periods presented. The results for the three months ended December 31, 2013 are not necessarily indicative of the results to be expected for the full fiscal year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s latest annual report on Form 10-K for the year ended September 30, 2013.
			•	Innovative Technology Solutions Corporation (ITSC) – acquired October 2003
			•	Alion - IPS Corporation (IPS) – acquired February 2004
			•	Alion - METI Corporation (METI) – acquired February 2005
			•	Alion - CATI Corporation (CATI) – acquired February 2005
			•	Alion International Corporation (Alion International) – established February 2005
			•	Alion Science and Technology (Canada) Corporation – established February 2005
			•	Alion - JJMA Corporation (JJMA) – acquired April 2005
			•	Alion - BMH Corporation (BMH) – acquired February 2006
			•	Washington Consulting, Inc. (WCI) – acquired February 2006
			•	Alion—MA&D Corporation (MA&D) – acquired May 2006
			•	Alion Offshore Services, Inc. (Alion Offshore) – established May 2006
			•	Washington Consulting Government Services, Inc. (WCGS) – established July 2007
			•	Alion Asia Corporation (Alion Asia) – established May 2012
			•	Alion Maritime India Private Limited (Alion India) – established May 2013
Fiscal, Quarter and Interim Periods	'	'
	Fiscal, Quarter and Interim Periods	Fiscal, Quarter and Interim Periods
	Alion’s fiscal year ends on September 30. The Company operates based on a three-month quarter, four-quarter fiscal year with quarters ending December 31, March 31, June 30, and September 30.	Alion’s fiscal year ends on September 30. The Company operates based on a three-month quarter, four-quarter fiscal year with quarters ending December 31, March 31, June 30, and September 30.
Use of Estimates	'	'
	Use of Estimates	Use of Estimates
	Preparing financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect amounts reported for assets and liabilities, disclosures of contingent assets and liabilities as of financial statement dates and amounts reported for operating results for each period presented. Actual results are likely to differ from those estimates, but management does not believe such differences will materially affect Alion’s financial position, results of operations, or cash flows.	Preparing financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect amounts reported for assets and liabilities, disclosures of contingent assets and liabilities as of financial statement dates and amounts reported for operating results for each period presented. Actual results are likely to differ from those estimates, but management does not believe such differences will materially affect Alion’s financial position, results of operations, or cash flows.
Revenue Recognition	'	'
	Revenue Recognition	Revenue Recognition
	Alion derives its revenue from delivering technology services under three types of contracts. Some contracts provide for reimbursement of costs plus fees; others are fixed-price or time-and-material type contracts. We recognize revenue when a contract has been executed, the contract price is fixed or determinable, delivery of services or products has occurred, and our ability to collect the contract price is considered reasonably assured. Alion applies the percentage-of-completion method in Accounting Standards Codification (ASC) 605 – Revenue Recognition to recognize revenue.	Alion derives its revenue from delivering technology services under three types of contracts. Some contracts provide for reimbursement of costs plus fees; others are fixed-price or time-and-material type contracts. We recognize revenue when a contract has been executed, the contract price is fixed or determinable, delivery of services or products has occurred, and our ability to collect the contract price is considered reasonably assured. Alion applies the percentage-of-completion method in Accounting Standards Codification (ASC) 605 – Revenue Recognition to recognize revenue.
	Alion recognizes revenue on cost-reimbursement contracts as it incurs costs and includes estimated fees earned. The Company recognizes time-and-material contract revenue at negotiated, fixed, contractually billable rates as it delivers labor hours and incurs other direct expenses. We use various performance measures under the percentage-of-completion method to recognize revenue for fixed-price contracts. Estimating contract costs at completion and recognizing revenue appropriately involve significant management estimates. Actual costs may differ from estimated costs and affect estimated profitability and revenue recognition timing. From time to time, facts develop that require us to revise estimated total costs or expected revenue. We record the cumulative effect of revised estimates in the period when the facts requiring revised estimates become known. We recognize the full amount of anticipated losses on any contract in the period a loss becomes known. For each of the periods presented, the cumulative effects of revised estimates were immaterial to the Company’s financial performance.
	U.S. federal government contracts are subject to periodic funding by our contracting agency customers. A customer may fund a contract at inception or incrementally throughout the period of performance as services are provided. If we determine contract funding is not probable, we defer revenue recognition until realization is probable. The federal government can audit Alion’s contract costs and adjust amounts through negotiation. The federal government considers Alion a major contractor and maintains an office on site. The Defense Contract Audit Agency (DCAA) is currently auditing our 2007 claimed indirect costs. We are negotiating our 2006 indirect rates and have settled our rates through 2005. We timely submitted our indirect cost proposals for all open fiscal years. We have recorded revenue on federal government contracts in amounts we expect to realize.	Alion recognizes revenue on cost-reimbursement contracts as it incurs costs and includes estimated fees earned. The Company recognizes time-and-material contract revenue at negotiated, fixed, contractually billable rates as it delivers labor hours and incurs other direct expenses. We use various performance measures under the percentage-of-completion method to recognize revenue for fixed-price contracts. Estimating contract costs at completion and recognizing revenue appropriately involve significant management estimates. Actual costs may differ from estimated costs and affect estimated profitability and revenue recognition timing. From time to time, facts develop that require us to revise estimated total costs or expected revenue. We record the cumulative effect of revised estimates in the period when the facts requiring revised estimates become known. We recognize the full amount of anticipated losses on any contract in the period a loss becomes known. For each of the periods presented, the cumulative effects of revised estimates were immaterial to the Company’s financial performance.
	We recognize revenue on unpriced change orders as we incur expenses and only to the extent it is probable we will recover such costs. The Company recognizes revenue in excess of costs on unpriced change orders only when management can also estimate beyond a reasonable doubt the amount of excess and experience provides a sufficient basis for recognition. Alion recognizes revenue on claims as expenses are incurred and only to the extent it is probable we will recover such costs and can reliably estimate the amount we will recover.	U.S. federal government contracts are subject to periodic funding by our contracting agency customers. A customer may fund a contract at inception or incrementally throughout the period of performance as services are provided. If we determine contract funding is not probable, we defer revenue recognition until realization is probable. The federal government can audit Alion’s contract costs and adjust amounts through negotiation. The federal government considers Alion a major contractor and maintains an office on site. The Defense Contract Audit Agency (DCAA) is currently auditing our 2007 claimed indirect costs. We are negotiating our 2006 indirect rates and have settled our rates through 2005. We timely submitted our indirect cost proposals for all open fiscal years. We have recorded revenue on federal government contracts in amounts we expect to realize.
		We recognize revenue on unpriced change orders as we incur expenses and only to the extent it is probable we will recover such costs. The Company recognizes revenue in excess of costs on unpriced change orders only when management can also estimate beyond a reasonable doubt the amount of excess and experience provides a sufficient basis for recognition. Alion recognizes revenue on claims as expenses are incurred and only to the extent it is probable we will recover such costs and can reliably estimate the amount we will recover.
Income Taxes	'	'
	Income Taxes	Income Taxes
	Alion accounts for income taxes by applying the provisions in currently enacted tax laws. We determine deferred income taxes based on the estimated future tax effects of differences between the financial statement and tax bases of our assets and liabilities. Deferred income tax provisions and benefits change as assets or liabilities change from year to year. In providing for deferred taxes, Alion considers the tax regulations of the jurisdictions where we operate; estimated future taxable income; and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies change, the carrying value of deferred tax assets and liabilities may require adjustment.	Alion accounts for income taxes by applying the provisions in currently enacted tax laws. We determine deferred income taxes based on the estimated future tax effects of differences between the financial statement and tax bases of our assets and liabilities. Deferred income tax provisions and benefits change as assets or liabilities change from year to year. In providing for deferred taxes, Alion considers the tax regulations of the jurisdictions where we operate; estimated future taxable income; and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies change, the carrying value of deferred tax assets and liabilities may require adjustment.
	Alion has a history of operating losses for both tax and financial statement purposes. The Company has recorded valuation allowances equal to deferred tax assets based on the likelihood that we may not be able to realize the value of these assets. Alion recognizes the benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain our position following an audit. For tax positions meeting the “more likely than not” threshold, we recognize the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.	Alion has a history of operating losses for both tax and financial statement purposes. The Company has recorded valuation allowances equal to deferred tax assets based on the likelihood that we may not be able to realize the value of these assets. Alion recognizes the benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain our position following an audit. For tax positions meeting the “more likely than not” threshold, we recognize the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
Going Concern Assumption	'	'
	Going Concern Assumption	Going Concern Assumption
	The accompanying financial statements are prepared on the going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Alion has a history of losses that has resulted, in part, in the Company not having the means to repay the principal associated with our Secured and Unsecured Notes as they come due on November 1, 2014 and February 1, 2015, respectively. In the first quarter of fiscal 2014, our Secured Notes were reclassified to current liabilities based on their November 1, 2014 maturity. Our Unsecured Notes will be reclassified to current liabilities in the second quarter of fiscal 2014.	The accompanying financial statements are prepared on the going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Alion has a history of losses that has resulted, in part, in the Company not having the means to repay the principal associated with our Secured and Unsecured Notes as they come due on November 1, 2014 and February 1, 2015, respectively. Further, liabilities in excess of our assets makes refinancing our debt more difficult and expensive, and an insufficient level of cash flow from operating activities to repay the Secured and Unsecured Notes at maturity, raises substantial doubt as to the Company’s ability to continue as a going concern.
	Our liabilities exceed our assets which makes refinancing our debt more difficult and expensive. Operating cash flow is insufficient to repay the Secured and Unsecured Notes at maturity, which raises substantial doubt as to the Company’s ability to continue as a going concern.	Management’s current forecasts of future results could differ materially due to general economic uncertainties, sequestration’s effect on government spending levels in the coming fiscal year, collections delays from the October 2013 government shutdown and risks associated with future federal government procurement and contracting actions. Management’s cash flow projections indicate that absent a refinancing transaction or series of transactions, the Company will be unable to pay the principal and accumulated unpaid interest on its Secured and Unsecured Notes when those instruments come due in November 2014 and February 2015.
	Management’s current forecasts of future results could differ materially due to general economic uncertainties, sequestration’s effect on government spending levels in the coming fiscal year, collections delays from the October 2013 government shutdown and risks associated with future federal government procurement and contracting actions. Management’s cash flow projections indicate that absent a refinancing transaction or series of transactions, the Company will be unable to pay the principal and accumulated unpaid interest on its Secured and Unsecured Notes when those instruments come due in November 2014 and February 2015.	Alion depends heavily on federal government prime contracts and subcontracts which account for nearly all the Company’s revenue. Interruptions in the government funding process, whether from federal budget delays, debt ceiling limitations, government shutdowns, sequestration or Department of Defense spending cuts could materially adversely affect the Company’s revenue and cash flows for the coming fiscal year and beyond. This could cause Alion to be unable to fund operations, meet debt service requirements or comply with the Credit Agreement’s Consolidated EBITDA covenant.
	Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of receiving an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this financial covenant. The Company paid no fee for this waiver.	Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of receiving an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this financial covenant. The Company paid no fee for this waiver
		If Alion were unable to meet the Credit Agreement Consolidated EBITDA covenant, the Company would be unable to borrow funds under the revolving credit facility which would remove a source of liquidity for the Company. Alion could be required to immediately repay any amount then outstanding under the Credit Agreement. The Company could seek an additional covenant waiver or an amendment to the Credit Agreement in order to preserve its ability to borrow funds as and when needed. The Credit Agreement expires on August 22, 2014. Management can provide no assurance that Alion would be able to obtain an amendment or waiver, or if one were available, that the terms would be favorable. If the Company were unable to obtain a requested waiver or amendment, it might be unable to pay its debts as they became due. In each of the past three fiscal years, Alion generated sufficient cash flow from operations to fulfill its financial commitments, including debt service.
	Alion depends heavily on federal government prime contracts and subcontracts which account for nearly all the Company’s revenue. Interruptions in the government funding process, whether from federal budget delays, debt ceiling limitations, government shutdowns, sequestration or Department of Defense spending cuts could materially adversely affect the Company’s revenue and cash flows for the coming fiscal year and beyond. This could cause Alion to be unable to fund operations, meet debt service requirements or comply with the Credit Agreement’s Consolidated EBITDA covenant.	Management is actively engaged in identifying additional potential sources of cash to refinance, retire or amend Alion’s existing debt agreements. We have reached a preliminary understanding with the holders of a majority of our outstanding Unsecured Notes regarding potential refinancing transactions involving our outstanding indebtedness and are negotiating a definitive agreement. However, Management can provide no assurance that Alion will be able to conclude a refinancing of its Unsecured Notes or that additional financing will be available to retire or replace its Secured Notes, and if available, that terms of any transaction would be favorable.
	If Alion were unable to meet the Credit Agreement Consolidated EBITDA covenant, the Company would be unable to borrow funds under the revolving credit facility which would remove a source of liquidity for the Company. Alion could be required to immediately repay any amount then outstanding under the Credit Agreement. The Company could seek an additional covenant waiver or an amendment to the Credit Agreement in order to preserve its ability to borrow funds as and when needed. The Credit Agreement expires on August 22, 2014. Management can provide no assurance that Alion would be able to obtain an amendment or waiver, or if one were available, that the terms would be favorable. If the Company were unable to obtain a requested waiver or amendment, it might be unable to pay its debts as they became due. In each of the past three fiscal years, Alion generated sufficient cash flow from operations to fulfill its financial commitments, including debt service.	On the basis of these risks and uncertainties, management has determined that there is substantial doubt about the Company’s ability to continue as a going concern. Alion’s audited consolidated financial statements do not include any adjustments to reflect the possible effects on the recoverability of assets or the amounts of liabilities that may result from resolving uncertainties about the Company’s ability to continue as a going concern.
	Management is actively engaged in efforts to refinance, retire or amend Alion’s existing debt agreements. On December 24, 2013, we executed a Refinancing Support Agreement with the holders of a majority of our outstanding Unsecured Notes regarding potential transactions to refinance our outstanding indebtedness. Management can provide no assurance that Alion will be able to conclude a refinancing of its Unsecured Notes or that additional financing will be available to retire or replace the Secured Notes, and if available, that terms of any transaction would be favorable.
	On the basis of these risks and uncertainties, management has determined that there is substantial doubt about the Company’s ability to continue as a going concern. Alion’s unaudited condensed consolidated financial statements do not include any adjustments to reflect the possible effects on the recoverability of assets or the amounts of liabilities that may result from resolving uncertainties about the Company’s ability to continue as a going concern.
Cash and Cash Equivalents	'	'
	Cash and Cash Equivalents	Cash and Cash Equivalents
	The Company considers cash in banks, and deposits with financial institutions with maturities of three months or less at time of purchase which it can liquidate without prior notice or penalty, to be cash and cash equivalents.	The Company considers cash in banks, and deposits with financial institutions with maturities of three months or less at time of purchase which it can liquidate without prior notice or penalty, to be cash and cash equivalents.
Accounts Receivable and Billings in Excess of Revenue Earned	'	'
	Accounts Receivable and Billings in Excess of Revenue Earned	Accounts Receivable and Billings in Excess of Revenue Earned
	Accounts receivable include billed accounts receivable and unbilled receivables. Unbilled receivables consist of costs and fees which are billable upon occurrence of a specific event, amounts billable after the balance sheet date and revenue in excess of billings on uncompleted contracts (accumulated project expenses and fees which were not billed or were not currently billable as of the date of the consolidated balance sheet). Unbilled accounts receivable include revenue recognized for customer-requested work Alion performed on new and existing contracts for which the Company had not received contracts or contract modifications. Accounts receivable are stated as estimated realized value. The allowance for doubtful accounts is Alion’s best estimate of the amount of probable losses in the Company’s existing billed and unbilled accounts receivable. The Company determines the allowance using specific identification and historical write-off experience based on receivable age. Billings in excess of revenue and advance collections from customers represent amounts received from or billed to customers in excess of project revenue recognized to date.	Accounts receivable include billed accounts receivable and unbilled receivables. Unbilled receivables consist of costs and fees which are billable upon occurrence of a specific event, amounts billable after the balance sheet date and revenue in excess of billings on uncompleted contracts (accumulated project expenses and fees which were not billed or were not currently billable as of the date of the consolidated balance sheet). Unbilled accounts receivable include revenue recognized for customer-requested work Alion performed on new and existing contracts for which the Company had not received contracts or contract modifications. Accounts receivable are stated as estimated realized value. The allowance for doubtful accounts is Alion’s best estimate of the amount of probable losses in the Company’s existing billed and unbilled accounts receivable. The Company determines the allowance using specific identification and historical write-off experience based on receivable age. Billings in excess of revenue and advance collections from customers represent amounts received from or billed to customers in excess of project revenue recognized to date.
Property, Plant and Equipment	'	'
	Property, Plant and Equipment	Property, Plant and Equipment
	Leasehold improvements, software and equipment are recorded at cost. Maintenance and repairs that do not add significant value or significantly lengthen an asset’s useful life are charged to current operations. Software and equipment are depreciated on the straight-line method over their estimated useful lives (typically 3 years for software and 5 years for equipment). Leasehold improvements are amortized on the straight-line method over the shorter of the asset’s estimated useful life or the life of the lease. Upon sale or retirement of an asset, costs and related accumulated depreciation are deducted from the accounts, and any gain or loss is recognized in the unaudited condensed consolidated statements of operations.	Leasehold improvements, software and equipment are recorded at cost. Maintenance and repairs that do not add significant value or significantly lengthen an asset’s useful life are charged to current operations. Software and equipment are depreciated on the straight-line method over their estimated useful lives (typically 3 years for software and 5 years for equipment). Leasehold improvements are amortized on the straight-line method over the shorter of the asset’s estimated useful life or the life of the lease. Upon sale or retirement of an asset, costs and related accumulated depreciation are deducted from the accounts, and any gain or loss is recognized in the audited consolidated statements of operations.
Goodwill	'	'
	Goodwill	Goodwill
	Alion assigns the purchase price paid to acquire the stock or assets of a business to the net assets acquired based on the estimated fair value of assets acquired and liabilities assumed. Goodwill is the purchase price in excess of the estimated fair value of the tangible net assets and separately identified intangible assets acquired. There have been no changes to goodwill carrying value this year.	Alion assigns the purchase price paid to acquire the stock or assets of a business to the net assets acquired based on the estimated fair value of assets acquired and liabilities assumed. Goodwill is the purchase price in excess of the estimated fair value of the tangible net assets and separately identified intangible assets acquired. There have been no changes to goodwill carrying value this year.
	The Company accounts for goodwill and other intangible assets in accordance with the provisions of ASC 350 – Intangibles-Goodwill and Other. Alion operates in one segment and tests goodwill at the reporting unit level. There are two reporting units. We review goodwill for impairment in the fourth quarter each year, and whenever events or circumstances indicate goodwill might be impaired. We are required to recognize an impairment loss to the extent our goodwill carrying value at the reporting unit level exceeds fair value. Evaluating goodwill involves significant management estimates. To date, our annual reviews have resulted in no goodwill impairment adjustments. See Note 8 for a detailed discussion of the Company’s goodwill impairment testing process.	The Company accounts for goodwill and other intangible assets in accordance with the provisions of ASC 350 – Intangibles-Goodwill and Other. Alion operates in one segment and tests goodwill at the reporting unit level. There are two reporting units. We review goodwill for impairment in the fourth quarter each year, and whenever events or circumstances indicate goodwill might be impaired. We are required to recognize an impairment loss to the extent our goodwill carrying value at the reporting unit level exceeds fair value. Evaluating goodwill involves significant management estimates. To date, our annual reviews have resulted in no goodwill impairment adjustments. See Note 9 for a detailed discussion of the Company’s goodwill impairment testing process.
Intangible Assets	'	'
	Intangible Assets	Intangible Assets
	Alion amortizes intangible assets as it consumes economic benefits over estimated useful lives. As of December 31, 2013, the Company had approximately $1.7 million in net intangible assets, including contracts purchased in the JJMA acquisition and purchased software licenses. The JJMA contract portfolio has a remaining useful life of approximately 1.5 years.	Alion amortizes intangible assets as it consumes economic benefits over estimated useful lives. As of September 30, 2013, the Company had approximately $2.0 million in net intangible assets, including contracts purchased in the JJMA acquisition and purchased software licenses. The JJMA contract portfolio has a remaining useful life of approximately 1.6 years.
Redeemable Common Stock	'	'
	Redeemable Common Stock	Redeemable Common Stock
	There is no public market for Alion’s redeemable common stock and therefore no observable price for its equity, individually or in the aggregate. The Employee Stock Ownership Plan (ESOP) Trust holds all the Company’s outstanding common stock. Under certain circumstances, ESOP beneficiaries can require the ESOP Trust to distribute the value of their beneficial interests. The Internal Revenue Code (IRC) and the Employee Retirement Income Security Act (ERISA) require the Company to offer ESOP participants who receive Alion common stock a liquidity put right. The put right requires the Company to purchase distributed shares at their then- current fair market value at any time during two put option periods. Common stock distributed by the ESOP Trust is subject to a right of first refusal. Prior to any subsequent transfer, shares must first be offered to the Company and then to the ESOP Trust. Eventual redemption of shares of Alion common stock as a result of distributions is outside the Company’s control. Therefore, Alion classifies its outstanding shares of redeemable common stock as other than permanent equity.	There is no public market for Alion’s redeemable common stock and therefore no observable price for its equity, individually or in the aggregate. The Employee Stock Ownership Plan (ESOP) Trust holds all the Company’s outstanding common stock. Under certain circumstances, ESOP beneficiaries can require the ESOP Trust to distribute the value of their beneficial interests. The Internal Revenue Code (IRC) and the Employee Retirement Income Security Act (ERISA) require the Company to offer ESOP participants who receive Alion common stock a liquidity put right. The put right requires the Company to purchase distributed shares at their then-current fair market value at any time during two put option periods. Common stock distributed by the ESOP Trust is subject to a right of first refusal. Prior to any subsequent transfer, shares must first be offered to the Company and then to the ESOP Trust. Eventual redemption of shares of Alion common stock as a result of distributions is outside the Company’s control. Therefore, Alion classifies its outstanding shares of redeemable common stock as other than permanent equity.
	At each reporting date, Alion is required to increase or decrease the reported value of its outstanding common stock to reflect its estimated redemption value. Management estimates the value of Alion’s obligation to repurchase its outstanding shares of redeemable common stock by considering, in part, the most recent price at which the Company was able to sell shares to the ESOP Trust. The reported value of outstanding redeemable common stock equals the current share price multiplied by total shares issued and outstanding.	At each reporting date, Alion is required to increase or decrease the reported value of its outstanding common stock to reflect its estimated redemption value. Management estimates the value of Alion’s obligation to repurchase its outstanding shares of redeemable common stock by considering, in part, the most recent price at which the Company was able to sell shares to the ESOP Trust. The reported value of outstanding redeemable common stock equals the current share price multiplied by total shares issued and outstanding.
	In its fiduciary capacity, the ESOP Trustee is independent of the Company and its management. Consistent with its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the ESOP Trustee may acquire or dispose of investments in Alion common stock. The Audit and Finance Committee of Alion’s Board of Directors reviews the reasonableness of the amount management has determined Alion should recognize for the Company’s obligation to repurchase shares of its outstanding redeemable common stock. The Audit and Finance Committee considers various factors in its review, including, in part, the most recent valuation report prepared for, and the share price selected by the ESOP Trustee.	In its fiduciary capacity, the ESOP Trustee is independent of the Company and its management. Consistent with its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the ESOP Trustee may acquire or dispose of investments in Alion common stock. The Audit and Finance Committee of Alion’s Board of Directors reviews the reasonableness of the amount management has determined Alion should recognize for the Company’s obligation to repurchase shares of its outstanding redeemable common stock. The Audit and Finance Committee considers various factors in its review, including, in part, the most recent valuation report prepared for, and the share price selected by the ESOP Trustee.
	Alion records changes in the reported value of its outstanding common stock through an offsetting charge or credit to accumulated deficit. The Company recognizes changes in the fair value of its redeemable common stock on March 31 and September 30 each year. The accumulated deficit at December 31, 2013, included a $67.5 million cumulative benefit for changes in share price which reduced the Company’s aggregate share redemption obligation. Outstanding redeemable common stock had an aggregate fair value of approximately $61.9 million as of December 31, 2013.
		Alion records changes in the reported value of its outstanding common stock through an offsetting charge or credit to accumulated deficit. The Company recognizes changes in the fair value of its redeemable common stock on March 31 and September 30 each year. The accumulated deficit at September 30, 2013, included a $67.5 million cumulative benefit for changes in share price which reduced the Company’s aggregate share redemption obligation. Outstanding redeemable common stock had an aggregate fair value of approximately $61.9 million as of September 30, 2013.
Concentration of Credit Risk	'	'
	Concentration of Credit Risk	Concentration of Credit Risk
	Alion is subject to credit risk for its cash equivalents and accounts receivable. The Company believes the high credit quality of its cash equivalent investments limits its credit risk with respect to such investments. Alion believes its concentration of credit risk with respect to accounts receivable is limited as the receivables are principally due from the federal government. Approximately 21% of the Company’s receivables are due from commercial customers including other prime contractors.	Alion is subject to credit risk for its cash equivalents and accounts receivable. The Company believes the high credit quality of its cash equivalent investments limits its credit risk with respect to such investments. Alion believes its concentration of credit risk with respect to accounts receivable is limited as the receivables are principally due from the federal government. Approximately 22% of the Company’s receivables are due from commercial customers including other prime contractors.
Fair Value of Financial Instruments	'	'
	Fair Value of Financial Instruments	Fair Value of Financial Instruments
	Alion is required to disclose the fair value of its financial instruments but is not required to record its senior long-term debt at fair value. See Note 10 for a discussion of Alion’s current and long-term debt and Note 11 for the related fair value disclosures. The fair value of cash, cash equivalents, accounts payable and accounts receivable does not differ materially from carrying value because of the short maturity of those instruments.	Alion is required to disclose the fair value of its financial instruments, but is not required to record its senior long term debt at fair value. See Note 11 for a discussion of Alion’s long term debt and Note 12 for the related fair value disclosures. The fair value of cash, cash equivalents, accounts payable and accounts receivable is not materially different from carrying value because of the short maturity of those instruments.
Off-Balance Sheet Financing Arrangements	'	'
	Off-Balance Sheet Financing Arrangements	Off-Balance Sheet Financing Arrangements
	Alion accounts for operating leases entered into in the routine course of business in accordance with ASC 840 – Leases. We have no off-balance sheet financing arrangements other than operating leases and letters of credit under our revolving credit facility. Alion has no relationship with any unconsolidated or special purpose entity and has not issued any associated guarantees.	Alion accounts for operating leases entered into in the routine course of business in accordance with ASC 840 Leases. We have no off-balance sheet financing arrangements other than operating leases and letters of credit under our revolving credit facility. Alion has no relationship with any unconsolidated or special purpose entity and has not issued any guarantees.

Accounts_Receivable_Tables

Accounts Receivable (Tables)	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Receivables [Abstract]	'							'
Schedule of Accounts Receivable	'							'
	Accounts receivable at December 31, 2013 and September 30, 2013 consisted of the following:							Accounts receivable at September 30 consisted of the following:
		December 31,			September 30,				September 30,
		2013			2013				2013			2012
		(In thousands)							(In thousands)
	Billed receivables and amounts billable as of the balance sheet date	$	104,581		$	102,211		Billed receivables and amounts billable as of the balance sheet date	$	102,211		$	94,028
	Unbilled receivables:							Unbilled receivables:
	Amounts billable after the balance sheet date		28,107			36,693		Amounts billable after the balance sheet date		36,693			48,730
	Revenues recorded in excess of milestone billings on fixed price contracts		3,825			3,289		Revenues recorded in excess of milestone billings on fixed price contracts		3,289			2,666
	Revenues recorded in excess of estimated contract value or funding		17,803			14,605		Revenues recorded in excess of estimated contract value or funding		14,605			18,998
	Retainages and other amounts billable upon contract completion		18,635			19,557		Retainages and other amounts billable upon contract completion		19,557			15,016
	Allowance for doubtful accounts		(3,988	)		(3,751	)	Allowance for doubtful accounts		(3,751	)		(4,145	)
	Total Accounts Receivable	$	168,963		$	172,604		Total Accounts Receivable	$	172,604		$	175,293

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Property Plant And Equipment [Abstract]	'							'
Schedule of Property, Plant and Equipment	'							'
	Property, Plant and Equipment							Property, Plant and Equipment
		December 31,			September 30,				September 30,
		2013			2013				2013			2012
		(In thousands)							(In thousands)
	Leasehold improvements	$	12,603		$	12,984		Leasehold improvements	$	12,984		$	12,168
	Equipment and software		35,314			35,203		Equipment and software		35,203			35,562
	Total cost		47,917			48,187		Total cost		48,187			47,730
	Less: accumulated depreciation and amortization		(38,847	)		(38,519	)	Less: accumulated depreciation and amortization		(38,519	)		(37,125	)
	Net Property, Plant and Equipment	$	9,070		$	9,668		Net Property, Plant and Equipment	$	9,668		$	10,605

Intangible_Assets_Tables

Intangible Assets (Tables)	3 Months Ended															12 Months Ended
	Dec. 31, 2013															Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'															'
Schedule of Intangible Assets	'															'
	The table below shows intangible assets as of December 31, 2013 and September 30, 2013.															The table below shows the intangible assets as of September 30, 2013 and 2012.
		December 31, 2013							September 30, 2013								September 30, 2013							September 30, 2012
		Gross		Accumulated			Net		Gross		Accumulated			Net			Gross		Accumulated			Net		Gross		Accumulated			Net
				Amortization							Amortization								Amortization							Amortization
		(In thousands)															(In thousands)
	Purchased contracts	$	111,635	$	(110,015	)	$	1,620	$	111,635	$	(109,795	)	$	1,840	Purchased contracts	$	111,635		(109,795	)		1,840	$	111,635	$	(106,935	)	$	4,700
	Internal use software and engineering designs		3,182		(3,067	)		115		3,182		(2,982	)		200	Internal use software and engineering designs		3,182		(2,982	)		200		3,182		(2,640	)		542
	Total	$	114,817	$	(113,082	)	$	1,735	$	114,817	$	(112,777	)	$	2,040	Total	$	114,817		(112,777	)		2,040	$	114,817	$	(109,575	)	$	5,242
Estimated Aggregate Amortization Expense	'															'
	Estimated aggregate amortization expense for the next five years and thereafter is as follows.															Estimated aggregate amortization expense for the next five years and thereafter is as follows.
		(In thousands)														Fiscal year ending	(In thousands)
																September 30,
	2014 (for the remainder of the fiscal year)	$	773													2014		1,079
	2015		737													2015		736
	2016		141													2016		141
	2017		51													2017		51
	2018		33													2018		33
	2019		—
	Thereafter		—														$	2,040
		$	1,735

Current_and_LongTerm_Debt_Tabl

Current and Long-Term Debt (Tables)	3 Months Ended								12 Months Ended
	Dec. 31, 2013								Sep. 30, 2013
Debt Disclosure [Abstract]	'								'
Interest Payable	'								'
			December 31,		September 30,
			2013		2013						September 30,
			(In thousands)								2013		2012
	Secured Notes		$	5,551	$	13,741					(In thousands)
	Unsecured Notes			10,039		4,017			Secured Notes			13,741		13,470
									Unsecured Notes		$	4,017	$	4,188
	Total		$	15,590	$	17,758
									Total		$	17,758	$	17,658
Principal Repayments	'								'
	As of December 31, 2013, Alion must make the following principal repayments (face value) for its outstanding debt. Unsecured Note face value exceeds carrying value and Secured Note face value exceeds carrying value. Carrying value includes debt issue costs which include the unamortized balances of: original issue discount; third-party debt issue expenses; and the initial fair value of common stock warrants issued in connection with the Secured Notes.								As of September 30, 2013, Alion must make the following principal repayments (face value) for its outstanding debt.
											2014		2015		Total
	Future Payments by Fiscal Year:		2014		2015		Total		Secured Notes and PIK Interest (1)		$	—	$	339,788	$	339,788
									Unsecured Notes (2)			—		235,000		235,000
	Secured Notes and PIK Interest(1)		$	—	$	339,788	$	339,788
	Unsecured Notes(2)			—		235,000		235,000	Total Principal Payments		$	—	$	574,788	$	574,788
	Total Principal Payments		$	—	$	574,788	$	574,788
									1	The Secured Notes due November 2014 include $310 million of debt issued in March 2010 and an estimated $29.8 million in PIK interest added to principal over the life of the notes. As of September 30, 2013, the $322.3 million carrying value on the face of the balance sheet included $310 million in principal, $19.8 million in PIK notes issued; $2.7 million in accrued PIK interest and is net of $10.3 million in aggregate unamortized debt issue costs. Initial debt issue costs consist of $7.7 million in original issue discount, $13.5 million in third-party costs and $20.8 million for the Secured Note warrants’ initial fair value.
									2	As of September 30, 2013, the Unsecured Notes due February 2015 include $235 million in principal and $1.2 million in unamortized debt issue costs (initially $7.1 million). The Company repurchased $10 million in Unsecured Notes in 2013 and $5 million in Unsecured Notes in 2011.
	1	The Secured Notes due November 2014 include $310 million of debt issued in March 2010 and an estimated $29.8 million in PIK interest added to principal over the life of the notes. As of December 31, 2013, the $326.3 million carrying value on the face of the balance sheet included $310 million in principal, $23.1 million in PIK notes issued; $1.1 million in accrued PIK interest and is net of $7.9 million in aggregate unamortized debt issue costs. Initial debt issue costs consist of $7.7 million in original issue discount, $13.5 million in third-party costs and $20.8 million for the Secured Note warrants’ initial fair value.
	2	As of December 31, 2013, the Unsecured Notes due February 2015 include $235 million in principal and approximately $1.0 million in unamortized debt issue costs (initially $7.1 million). Since issuing the Unsecured Notes, the Company has repurchased $15 million in principal.

Fair_Value_Measurement_Tables

Fair Value Measurement (Tables)	3 Months Ended													12 Months Ended
	Dec. 31, 2013													Sep. 30, 2013
Fair Value Disclosures [Abstract]	'													'
Face Value, Net Carrying Value and Fair Value of Secured and Unsecured Notes	'													'
	The table below sets out the face value, net carrying value and fair value of Alion’s Secured and Unsecured Notes. The fair values disclosed below are based on quoted market prices for Alion’s outstanding notes. This is a Level 2 measurement.													The table below sets out the face value, net carrying value and fair value of Alion’s Secured and Unsecured Notes. The fair values disclosed below are based on quoted market prices for Alion’s outstanding notes. This is a Level 2 measurement.
		December 31, 2013						September 30, 2013							September 30, 2013						September 30, 2012
		(In thousands)													(In thousands)
		Secured			Unsecured			Secured			Unsecured				Senior			Senior			Senior			Senior
		Notes			Notes			Notes			Notes				Secured			Unsecured			Secured			Unsecured
	Face value of original notes outstanding	$	310,000		$	235,000		$	310,000		$	235,000			Notes			Notes			Notes			Notes
	PIK interest notes issued		23,086			—			19,788			—		Face value of original notes outstanding	$	310,000		$	235,000		$	310,000		$	245,000
														PIK interest notes issued		19,788			—			13,293			—
	Face value of outstanding notes	$	333,086		$	235,000		$	329,788		$	235,000
	PIK interest notes to be issued		1,111			—			2,748			—		Face value of outstanding notes	$	329,788		$	235,000		$	323,293		$	245,000
														PIK interest notes to be issued		2,748			—			2,692			—
	Face value of notes outstanding and notes to be issued	$	334,197		$	235,000		$	332,536		$	235,000
	Less: unamortized debt issue costs		(7,883	)		(962	)		(10,250	)		(1,168	)	Face value of notes outstanding and notes to be issued	$	332,536		$	235,000		$	325,985		$	245,000
														Less: unamortized debt issue costs		(10,250	)		(1,168	)		(19,483	)		(2,077	)
	Carrying value	$	326,314		$	234,038		$	322,286		$	233,832
														Carrying value	$	322,286		$	233,832		$	306,502		$	242,923
	Fair value of outstanding notes	$	339,681		$	165,894		$	335,295		$	151,928		Fair value of outstanding notes	$	335,295		$	151,928		$	303,598		$	141,605

Leases_Tables

Leases (Tables)	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Leases [Abstract]	'							'
Future Minimum Lease Payments	'							'
	Alion subleases some excess capacity to subtenants under non-cancelable operating leases.							Alion subleases some excess capacity to subtenants under non-cancelable operating leases.
	Lease Payments for Fiscal Years Ending	(In thousands)						Lease Payments for Fiscal Years Ending	(In thousands)
	2014 (for the remainder of fiscal year)	$	19,497					2014	$	26,009
	2015		25,076					2015		24,875
	2016		21,183					2016		21,041
	2017		17,783					2017		17,804
	2018		14,931					2018		14,931
	2019		6,162					And thereafter		19,109
	And thereafter		12,947
								Gross lease payments	$	123,769
	Gross lease payments	$	117,579					Less: non-cancelable subtenant receipts		(1,711	)
	Less: non-cancelable subtenant receipts		(1,593	)
								Net lease payments	$	122,058
	Net lease payments	$	115,986
Composition of Total Rent Expense	'							'
	Composition of Total Rent Expense							Composition of Total Rent Expense
		Three Months Ended							September 30,
		December 31,							2013			2012			2011
		2013			2012				(In thousands)
		(In thousands)						Minimum rentals	$	21,530		$	20,639		$	21,992
	Minimum rentals	$	5,515		$	5,301		Less: Sublease rental income		(600	)		(156	)		(1,610	)
	Less: Sublease rental income		(143	)		(104	)
								Total rent expense, net	$	20,930		$	20,483		$	20,382
	Total rent expense, net	$	5,372		$	5,197

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Summary of Net Deferred Tax Liability	'
	The Company’s effective tax rate for the three months ended December 31, 2013 was -10.4% and -18.8% for the three months ended December 31, 2012. As of December 31, 2013 and September 30, 2013 the net deferred tax liability was:
		December 31,			September 30,
		2013			2013
		(In thousands)
	Current deferred tax asset	$	7,355		$	9,228
	Noncurrent deferred tax asset		98,007			87,812
	Valuation allowance		(105,362	)		(97,040	)
	Noncurrent deferred tax liability		(59,873	)		(58,130	)
	Net deferred tax liability	$	(59,873	)	$	(58,130	)

GuarantorNonGuarantor_Unaudite1

Guarantor/Non-Guarantor Unaudited Condensed Consolidated Financial Information (Tables)	3 Months Ended																12 Months Ended
	Dec. 31, 2013																Sep. 30, 2013
Text Block [Abstract]	'																'
Condensed Consolidating Balance Sheet	'																'
	Condensed Consolidating Balance Sheet as of December 31, 2013 (unaudited)																Condensed Consolidating Balance Sheet Information at September 30, 2013
		Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
					Companies			Guarantor													Companies			Companies
								Companies										(In thousands)
		(In thousands)															Current assets:
	Current assets:																Cash and cash equivalents	$	25,617		$	(24	)	$	20		$	—		$	25,613
	Cash and cash equivalents	$	4,670		$	(10	)	$	27		$	—		$	4,687		Accounts receivable, net		169,304			2,735			565			—			172,604
	Accounts receivable, net		166,283			2,038			642			—			168,963		Receivable due from ESOP Trust		930			—			—			—			930
	Prepaid expenses and other current assets		5,587			36			25			—			5,648		Prepaid expenses and other current assets		4,449			188			(154	)		—			4,483
	Total current assets		176,540			2,064			694			—			179,298		Total current assets		200,300			2,899			431			—			203,630
	Property, plant and equipment, net		8,552			515			3			—			9,070		Property, plant and equipment, net		9,139			525			4			—			9,668
	Intangible assets, net		1,735			—			—			—			1,735		Intangible assets, net		2,040			—			—			—			2,040
	Goodwill		398,921			—			—			—			398,921		Goodwill		398,921			—			—			—			398,921
	Investment in subsidiaries		28,710			—			—			(28,710	)		—		Investment in subsidiaries		28,420			—			—			(28,420	)		—
	Intercompany receivables		1,963			28,536			—			(30,499	)		—		Intercompany receivables		1,906			27,828			—			(29,734	)		—
	Other assets		10,364			—			4			—			10,368		Other assets		10,363			—			4			—			10,367
	Total assets	$	626,785		$	31,115		$	701		$	(59,209	)	$	599,392		Total assets	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
	Current liabilities:																Current liabilities:
	Interest payable	$	15,590		$	—		$	—		$	—		$	15,590		Interest payable	$	17,758		$	—		$	—		$	—		$	17,758
	Secured notes		326,313			—			—			—			326,313		Trade accounts payable		61,563			58			1			—			61,622
	Trade accounts payable		59,465			40			31			—			59,536		Accrued liabilities		39,169			144			80			—			39,393
	Accrued liabilities		36,710			96			103			—			36,909		Accrued payroll and related liabilities		37,404			517			33			—			37,954
	Accrued payroll and related liabilities		31,399			303			31			—			31,733		Billings in excess of costs revenue earned		4,250			84			—			—			4,334
	Billings in excess of revenue earned		4,452			110			—			—			4,562
																	Total current liabilities		160,144			803			114			—			161,061
	Total current liabilities		473,929			549			165			—			474,643		Intercompany payables		27,826			153			1,754			(29,733	)		—
	Intercompany payables		28,537			—			1,962			(30,499	)		—		Secured Notes		322,286			—			—			—			322,286
	Unsecured notes		234,038			—			—			—			234,038		Unsecured Notes		233,832			—			—			—			233,832
	Accrued compensation and benefits, excluding current portion		5,998			—			—			—			5,998		Accrued compensation and benefits, excluding current portion		5,736			—			—			—			5,736
	Non-current portion of lease obligations		12,110			430			—			—			12,540		Non-current portion of lease obligations		12,374			447			—			—			12,821
	Deferred income taxes		59,873			—			—			—			59,873		Deferred income taxes		58,130			—			—			—			58,130
	Commitments and contingencies																Commitments and contingencies		—			—			—			—			—
	Redeemable common stock		61,896			—			—			—			61,896		Redeemable common stock		61,895			—			—			—			61,895
	Common stock warrants		20,785			—			—			—			20,785		Common stock warrants		20,785			—			—			—			20,785
	Common stock of subsidiaries		—			4,084			9			(4,093	)		—		Common stock of subsidiaries		—			4,084			9			(4,093	)		—
	Accumulated other comprehensive loss		130			—			—			—			130		Accumulated other comprehensive loss		130			—			—			—			130
	Accumulated deficit		(270,511	)		26,052			(1,435	)		(24,617	)		(270,511	)	Accumulated surplus (deficit)		(252,049	)		25,765			(1,438	)		(24,328	)		(252,050	)
	Total liabilities, redeemable common stock and accumulated deficit	$	626,785		$	31,115		$	701		$	(59,209	)	$	599,392		Total liabilities, redeemable common stock and stockholder’s deficit	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
	Condensed Consolidating Balance Sheet as of September 30, 2013 (unaudited)																Condensed Consolidating Balance Sheet Information at September 30, 2012
		Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
								Guarantor													Companies			Companies
								Companies										(In thousands)
		(In thousands)															Current assets:
	Current assets:																Cash and cash equivalents	$	27,271		$	(44	)	$	—		$	—		$	27,227
	Cash and cash equivalents	$	25,617		$	(24	)	$	20		$	—		$	25,613		Accounts receivable, net		172,365			2,783			145			—			175,293
	Accounts receivable, net		169,304			2,735			565			—			172,604		Receivable due from ESOP Trust		1,129			—			—			—			1,129
	Receivable due from ESOP Trust		930			—			—			—			930		Prepaid expenses and other current assets		5,378			70			—			—			5,448
	Prepaid expenses and other current assets		4,449			188			(154	)		—			4,483
																	Total current assets		206,143			2,809			145			—			209,097
	Total current assets		200,300			2,899			431			—			203,630		Property, plant and equipment, net		10,064			529			12			—			10,605
	Property, plant and equipment, net		9,139			525			4			—			9,668		Intangible assets, net		5,242			—			—			—			5,242
	Intangible assets, net		2,040			—			—			—			2,040		Goodwill		398,921			—			—			—			398,921
	Goodwill		398,921			—			—			—			398,921		Investment in subsidiaries		27,994			—			—			(27,994	)		—
	Investment in subsidiaries		28,420			—			—			(28,420	)		—		Intercompany receivables		1,438			27,475			—			(28,913	)		—
	Intercompany receivables		1,906			27,828			—			(29,734	)		—		Other assets		11,427			—			4			—			11,431
	Other assets		10,363			—			4			—			10,367
																	Total assets	$	661,229		$	30,813		$	161		$	(56,907	)	$	635,296
	Total assets	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
																	Current liabilities:
	Current liabilities:																Interest payable	$	17,658		$	—		$	—		$	—		$	17,658
	Interest payable	$	17,758		$	—		$	—		$	—		$	17,758		Trade accounts payable		44,582			201			10			—			44,793
	Trade accounts payable		61,563			58			1			—			61,622		Accrued liabilities		52,265			190			5			—			52,460
	Accrued liabilities		39,169			144			80			—			39,393		Accrued payroll and related liabilities		39,305			589			32			—			39,926
Accrued payroll and related liabilities		37,404			517			33			—			37,954		Billings in excess of costs revenue earned		2,656			6			4			—			2,666
Billings in excess of costs revenue earned		4,250			84			—			—			4,334
																Total current liabilities		156,466			986			51			—			157,503
Total current liabilities		160,144			803			114			—			161,061		Intercompany payables		27,476			—			1,437			(28,913	)		—
Intercompany payables		27,826			153			1,754			(29,733	)		—		Secured Notes		306,502			—			—			—			306,502
Secured Notes		322,286			—			—			—			322,286		Unsecured Notes		242,923			—			—			—			242,923
Unsecured Notes		233,832			—			—			—			233,832		Accrued compensation and benefits, excluding current portion		5,905			—			—			—			5,905
Accrued compensation and benefits, excluding current portion		5,736			—			—			—			5,736		Non-current portion of lease obligations		11,858			506			—			—			12,364
Non-current portion of lease obligations		12,374			447			—			—			12,821		Deferred income taxes		51,156			—			—			—			51,156
Deferred income taxes		58,130			—			—			—			58,130		Commitments and contingencies
Redeemable common stock		61,895			—			—			—			61,895		Redeemable common stock		110,740			—			—			—			110,740
Common stock of subsidiaries		—			4,084			9			(4,093	)		—		Common stock warrants		20,785			—			—			—			20,785
Commitments and contingencies																Common stock of subsidiaries		—			4,084			—			(4,084	)		—
Common stock warrants		20,785			—			—			—			20,785		Accumulated other comprehensive loss		(149	)		—			—			—			(149	)
Accumulated other comprehensive loss		130			—			—			—			130		Accumulated surplus (deficit)		(272,433	)		25,237			(1,327	)		(23,910	)		(272,433	)
Accumulated surplus (deficit)		(252,049	)		25,765			(1,438	)		(24,328	)		(252,050	)
																Total liabilities, redeemable common stock and stockholder’s deficit	$	661,229		$	30,813		$	161		$	(56,907	)	$	635,296
Total liabilities, redeemable common stock and accumulated deficit	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
Condensed Consolidating Statement of Operations and Comprehensive Loss	'																'
	Condensed Consolidating Statement of Operations and Comprehensive Loss for the Three Months Ended December 31, 2013 (unaudited)																Condensed Consolidating Statement of Comprehensive Loss
		Parent			Guarantor			Non-			Eliminations			Consolidated				Year Ended September 30, 2013
					Companies			Guarantor										Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
								Companies													Companies			Companies
		(In thousands)																(In thousands)
	Contract revenue	$	183,384			1,771			225			—		$	185,380		Contract revenue	$	839,608		$	8,627		$	737		$	—		$	848,972
	Direct contract expense		144,060			1,091			124			—			145,275		Direct contract expenses		663,380			5,638			486			—			669,504
	Gross profit		39,324			680			101			—			40,105		Gross profit		176,228			2,989			251			—			179,468
	Operating expenses		18,385			392			87						18,864		Operating expenses		81,838			1,972			318			—			84,128
	General and administrative		18,983			1			9			—			18,993		General and administrative		52,491			604			44			—			53,139
	Operating income		1,956			287			5			—			2,248		Operating income (loss)		41,899			413			(111	)		—			42,201
	Other income (expense):																Other income (expense):
	Interest income		11			—			—			—			11		Interest income		55			—			—			—			55
	Interest expense		(18,948	)		—			—			—			(18,948	)	Interest expense		(75,700	)		—			—			—			(75,700	)
	Other		(28	)					—			—			(28	)	Other		(200	)		116			—			—			(84	)
	Equity in net income (loss) of subsidiaries		292						—			(292	)		—		Gain on debt extinguishment		3,913			—			—			—			3,913
																	Equity in net income (loss) of subsidiaries		418			—			—			(418	)		—
	Total other expenses		(18,673	)		—			—			(292	)		(18,965	)
																	Total other income (expense)		(71,514	)		116			—			(418	)		(71,816	)
	(Loss) income before taxes		(16,717	)		287			5			(292	)		(16,717	)	Income (loss) before taxes		(29,615	)		529			(111	)		(418	)		(29,615	)
	Income tax expense		(1,745	)		—			—			—			(1,745	)	Income tax expense		(6,977	)		—			—			—			(6,977	)
	Net loss	$	(18,462	)	$	287		$	5		$	(292	)	$	(18,462	)	Net income (loss)	$	(36,592	)	$	529		$	(111	)	$	(418	)	$	(36,592	)
	Other comprehensive income																Other comprehensive income:
	Postretirement actuarial gains		—			—			—			—			—		Postretirement actuarial gains		279			—			—			—			279
	Comprehensive income (loss)	$	(18,462	)	$	287		$	5		$	(292	)	$	(18,462	)	Comprehensive income (loss)	$	(36,313	)		529			(111	)		(418	)		(36,313	)
																	Condensed Consolidating Statement of Comprehensive Loss
	Condensed Consolidating Statement of Operations and Comprehensive Loss for the Three Months Ended December 31, 2012 (unaudited)
																		Year Ended September 30, 2012
		Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-			Eliminations			Consolidated
					Companies			Guarantor													Companies			Guarantor
								Companies																Companies
		(In thousands)																(In thousands)
	Contract revenue	$	202,057		$	2,218		$	54		$	—		$	204,329		Contract revenue	$	802,664		$	14,015		$	525		$	—		$	817,204
	Direct contract expense		159,162			1,337			136			—			160,635		Direct contract expenses		624,788			7,743			300			—			632,831
	Gross profit		42,895			881			(82	)		—			43,694		Gross profit		177,876			6,272			225			—			184,373
	Operating expenses		21,621			560			69			—			22,250		Operating expenses		88,736			2,531			227			—			91,494
	General and administrative		11,734			49			21			—			11,804		General and administrative		52,123			156			162			—			52,441
	Operating income (loss)		9,540			272			(172	)		—			9,640		Operating income (loss)		37,017			3,585			(164	)		—			40,438
	Other income (expense):																Other income (expense):
	Interest income		17			—			—			—			17		Interest income		78			—			—			—			78
	Interest expense		(18,919	)		—			—			—			(18,919	)	Interest expense		(74,934	)		—			—			—			(74,934	)
	Other		(15	)		—			—			—			(15	)	Other		(63	)		9			(1	)		—			(55	)
	Equity in net income of subsidiaries		100			—			—			(100	)		—		Equity in net income (loss) of subsidiaries		3,429			—			—			(3,429	)		—
	Total other (expense) income		(18,817	)		—			—			(100	)		(18,917	)	Total other income (expense)		(71,490	)		9			(1	)		(3,429	)		(74,911	)
																	Income (loss) before taxes		(34,473	)		3,594			(165	)		(3,429	)		(34,473	)
	(Loss) income before taxes		(9,277	)		272			(172	)		(100	)		(9,277	)	Income tax expense		(6,974	)		—			—			—			(6,974	)
	Income tax expense		(1,744	)		—			—			—			(1,744	)
																	Net income (loss)	$	(41,447	)	$	3,594		$	(165	)	$	(3,429	)	$	(41,447	)
	Net income (loss)	$	(11,021	)	$	272		$	(172	)	$	(100	)	$	(11,021	)
																	Other comprehensive income:
	Other comprehensive income:																Postretirement actuarial gains		26			—			—			—			26
	Postretirement actuarial gains		—			—			—			—			—
																	Comprehensive income (loss)	$	(41,421	)		3,594			(165	)		(3,429	)		(41,421	)
	Comprehensive income (loss)	$	(11,021	)	$	272		$	(172	)	$	(100	)	$	(11,021	)
																	Condensed Consolidating Statement of Comprehensive Loss
																		Year Ended September 30, 2011
																		Parent			Guarantor			Non-			Eliminations			Consolidated
																					Companies			Guarantor
																								Companies
																		(In thousands)
																	Contract revenue	$	769,467		$	17,025		$	822		$	—		$	787,314
																	Direct contract expenses		593,600			9,333			548			—			603,481
																	Gross profit		175,867			7,692			274			—			183,833
																Operating expenses		79,871			3,076			88			—			83,035
																General and administrative		64,374			620			311			—			65,305
																Operating income (loss)		31,622			3,996			(125	)		—			35,493
																Other income (expense):
																Interest income		45			—			—			—			45
																Interest expense		(73,919	)		—			—			—			(73,919	)
																Other		(535	)		568			(1	)		—			32
																Gain on debt extinguishment		939			—			—			—			939
																Equity in net income (loss) of subsidiaries		4,438			—			—			(4,438	)		—
																Total other income (expense)		(69,032	)		568			(1	)		(4,438	)		(72,903	)
																Income (loss) before taxes		(37,410	)		4,564			(126	)		(4,438	)		(37,410	)
																Income tax expense		(6,974	)		—			—			—			(6,974	)
																Net income (loss)	$	(44,384	)	$	4,564		$	(126	)	$	(4,438	)	$	(44,384	)
																Other comprehensive income:
																Post retirement actuarial gains		55			—			—			—			55
																Comprehensive income (loss)		(44,329	)		4,564			(126	)		(4,438	)		(44,329	)
Condensed Consolidating Statement of Cash Flows	'																'
	Condensed Consolidating Statement of Cash Flows for the Three Months Ended December 31, 2013 (unaudited)																Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2013
		Parent			Guarantor			Non-			Consolidated
					Companies			Guarantor										Parent			Guarantors			Non-			Consolidated
								Companies																Guarantors
		(In thousands)																(In thousands)
	Net cash (used in) provided by operating activities	$	(19,934	)	$	24		$	7		$	(19,903	)				Net cash provided by operating activities	$	10,666		$	97		$	20		$	10,783
																	Cash flows from investing activities:
	Cash flows from investing activities:																Capital expenditures		(1,792	)		(77	)		—			(1,869	)
	Capital expenditures		(263	)		(10	)		—			(273	)
																	Net cash provided by (used in) investing activities		(1,792	)		(77	)		—			(1,869	)
	Net cash used in investing activities		(263	)		(10	)		—			(273	)				Cash flows from financing activities:
	Cash flows from financing activities:																Repurchase of Unsecured Notes		(6,030	)		—			—			(6,030	)
	Payment of debt issue costs		(750	)		—			—			(750	)				Revolver borrowings		16,461			—			—			16,461
	Revolver borrowings		10,000			—			—			10,000					Revolver repayments		(16,461	)		—			—			(16,461	)
	Revolver payments		(10,000	)		—			—			(10,000	)				Loan to ESOP Trust		(1,907	)		—			—			(1,907	)
	Redeemable common stock purchased from ESOP Trust		(934	)		—			—			(934	)				ESOP loan repayment		1,907			—			—			1,907
	Redeemable common stock sold to ESOP Trust		934			—			—			934					Redeemable common stock purchased from ESOP Trust		(6,664	)		—			—			(6,664	)
																	Redeemable common stock sold to ESOP Trust		2,166			—			—			2,166
	Net cash used in financing activities		(750	)		—			—			(750	)
	Net (decrease) increase in cash and cash equivalents		(20,947	)		14			7			(20,926	)				Net cash used in financing activities		(10,528	)		—			—			(10,528	)
	Cash and cash equivalents at beginning of period		25,617			(24	)		20			25,613
																	Net increase (decrease) in cash and cash equivalents		(1,654	)		20			20			(1,614	)
	Cash and cash equivalents at end of period	$	4,670		$	(10	)	$	27		$	4,687					Cash and cash equivalents at beginning of period		27,271			(44	)		—			27,227
																	Cash and cash equivalents at end of period	$	25,617		$	(24	)	$	20		$	25,613
	Condensed Consolidating Statement of Cash Flows for the Three Months Ended December 31, 2012 (unaudited)
																	Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2012
		Parent			Guarantor			Non-			Consolidated
					Companies			Guarantor
								Companies										Parent			Guarantors			Non-			Consolidated
		(In thousands)																						Guarantors
	Net cash (used in) provided by operating activities	$	(6,337	)	$	15		$	5		$	(6,317	)					(In thousands)
																	Net cash provided by (used in) operating activities	$	12,700		$	(19	)	$	—		$	12,681
	Cash flows from investing activities:																Cash flows from investing activities:
	Capital expenditures		(603	)		—			—			(603	)				Capital expenditures		(2,733	)		2			—			(2,731	)
	Net cash used in investing activities		(603	)		—			—			(603	)				Net cash provided by (used in) investing activities		(2,733	)		2			—			(2,731	)
	Cash flows from financing activities:
	Redeemable common stock purchased from ESOP Trust		(1,975	)		—			—			(1,975	)				Cash flows from financing activities:
																	Revolver borrowings		26,000			—			—			26,000
	Net cash provided by financing activities		(846	)		—			—			(846	)				Revolver repayments		(26,000	)		—			—			(26,000	)
	Net increase (decrease) in cash and cash equivalents		(7,786	)		15			5			(7,766	)				Loan to ESOP Trust		(477	)		—			—			(477	)
	Cash and cash equivalents at beginning of period		27,271			(44	)		—			27,227					ESOP loan repayment		477			—			—			477
																	Redeemable common stock purchased from ESOP Trust		(4,843	)		—			—			(4,843	)
	Cash and cash equivalents at end of period	$	19,485		$	(29	)	$	5		$	19,461					Redeemable common stock sold to ESOP Trust		1,302			—			—			1,302
																	Net cash used in financing activities		(3,541	)		—			—			(3,541	)
																	Net increase (decrease) in cash and cash equivalents		6,426			(17	)		—			6,409
																	Cash and cash equivalents at beginning of period		20,845			(27	)		—			20,818
																	Cash and cash equivalents at end of period	$	27,271		$	(44	)	$	—		$	27,227
																	Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2011
																		Parent			Guarantors			Non-			Consolidated
																								Guarantors
																		(In thousands)
																	Net cash provided by operating activities	$	5,061		$	636		$	24		$	5,721
																	Cash flows from investing activities:
																	Capital expenditures		(5,694	)		(588	)		(23	)		(6,305	)
																	Proceeds from sale of fixed assets		14			—			—			14
																	Net cash used in investing activities		(5,680	)		(588	)		(23	)		(6,291	)
																	Cash flows from financing activities:
																	Payment of debt issuance cost		(710	)		—			—			(710	)
																	Repurchase unsecured notes		(3,993	)		—			—			(3,993	)
																	Revolver borrowings		17,000			—			—			17,000
																Revolver payments		(17,000	)		—			—			(17,000	)
																Loan to ESOP Trust		(776	)		—			—			(776	)
																ESOP loan repayment		776			—			—			776
																Redeemable common stock purchased from ESOP Trust		(5,762	)		—			—			(5,762	)
																Redeemable common stock sold to ESOP Trust		5,158			—			—			5,158
																Net cash used in financing activities		(5,307	)		—			—			(5,307	)
																Net increase (decrease) in cash and cash equivalents		(5,926	)		48			1			(5,877	)
																Cash and cash equivalents at beginning of period		26,770			(74	)		(1	)		26,695
																Cash and cash equivalents at end of period	$	20,844		$	(26	)	$	—		$	20,818

Description_and_Formation_of_t1

Description and Formation of the Business - Additional Information (Detail) (USD $)	Dec. 20, 2002
In Millions, unless otherwise specified
Business Combinations [Abstract]	'
Acquisition cost	$127.30

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
	Reporting_Unit		Reporting_Unit
	Segment		Contract
	Contract		Segment
Schedule Of Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Number of contracts	3	'	3	'	'
Maturity period of cash and cash equivalents	'3 months	'	'3 months	'	'
Number of segments	1	'	1	'	'
Number of reporting units	2	'	2	'	'
Changes to goodwill during period	'	'	$0	$0	$0
Goodwill impairment	0	0	0	'	'
Intangible assets, net	1,735,000	2,040,000	2,040,000	5,242,000	'
Intangible assets, amortization period	'	'	'1 year 7 months 6 days	'	'
Equity market information	'There is no public market for Alions redeemable common stock and therefore no observable price for its equity, individually or in the aggregate.	'	'	'	'
Benefit from decreased share redemption obligation	67,500,000	'	67,500,000	'	'
Redeemable common stock	$61,896,000	$61,895,000	$61,895,000	$110,740,000	'
Percentage of receivables due from commercial customers	21.00%	22.00%	22.00%	'	'
Secured Notes and Warrants [Member]	'	'	'	'	'
Schedule Of Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Maturity of debt	1-Nov-14	'	1-Nov-14	'	'
Unsecured Notes [Member]	'	'	'	'	'
Schedule Of Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Maturity of debt	1-Feb-15	'	1-Feb-15	'	'
Revolving Credit Facility [Member]	'	'	'	'	'
Schedule Of Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Expiration date of agreement	22-Aug-14	'	22-Aug-14	'	'
Minimum [Member]	'	'	'	'	'
Schedule Of Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Percentage of income tax benefit	50.00%	'	50.00%	'	'
Maximum [Member]	'	'	'	'	'
Schedule Of Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Intangible assets, amortization period	'1 year 6 months	'	'	'	'
Software [Member]	'	'	'	'	'
Schedule Of Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Property, plant and equipment, estimated useful lives	'3 years	'	'3 years	'	'
Equipment [Member]	'	'	'	'	'
Schedule Of Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Property, plant and equipment, estimated useful lives	'5 years	'	'5 years	'	'

Employee_Stock_Ownership_Plan_1

Employee Stock Ownership Plan (ESOP) and ESOP Trust - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'
Employee stock ownership plan period of service requirement	'1 year	'1 year
Employee stock ownership plan amendment description	'The Company amended the Plan to eliminate the one year service requirement for employer 401(k) matching contributions; to automatically enroll new hires in the Plan's 401(k) component; and to designate profit sharing contributions exclusively in Alion common stock.	'The Company amended the Plan to eliminate the one year service requirement for employer 401(k) matching contributions; to automatically enroll new hires in the Plan's 401(k) component; and to designate profit sharing contributions exclusively in Alion common stock.

Loss_Per_Share_Additional_Info

Loss Per Share - Additional Information (Detail)	0 Months Ended	1 Months Ended
	Mar. 22, 2010	Mar. 22, 2010	Mar. 31, 2010
	Unit	Unit	Unit
Earnings Per Share [Line Items]	'	'	'
Common stock purchased	602,614	602,614	'
Exercise price of warrants	0.01	0.01	'
Expiry date	15-Mar-17	15-Mar-17	'
Secured Notes and Warrants [Member]	'	'	'
Earnings Per Share [Line Items]	'	'	'
Secured notes and warrants issued	310,000	310,000	310,000

Redeemable_Common_Stock_Additi

Redeemable Common Stock - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2013	Mar. 31, 2013
	Age	Age	ESOP [Member]	ESOP [Member]	ESOP [Member]
			Period
Common Equity [Line Items]	'	'	'	'	'
Distribution period of the fair value of vested ESOP	'5 years	'5 years	'	'	'
Age of participant's retirement	65	65	'	'	'
Period of delay in ESOP plan balance distribution	'6 years	'6 years	'	'	'
Subsequent distribution period of the fair value of vested ESOP	'5 years	'5 years	'	'	'
Estimated fair value share price	'	'	$8.10	$8.10	$16.25
Number of put option periods	'	'	2	'	'

Accounts_Receivable_Accounts_R

Accounts Receivable - Accounts Receivable (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Receivables [Abstract]	'	'	'
Billed receivables and amounts billable as of the balance sheet date	$104,581	$102,211	$94,028
Unbilled receivables:	'	'	'
Amounts billable after the balance sheet date	28,107	36,693	48,730
Revenues recorded in excess of milestone billings on fixed price contracts	3,825	3,289	2,666
Revenues recorded in excess of estimated contract value or funding	17,803	14,605	18,998
Retainages and other amounts billable upon contract completion	18,635	19,557	15,016
Allowance for doubtful accounts	-3,988	-3,751	-4,145
Total Accounts Receivable	$168,963	$172,604	$175,293

Accounts_Receivable_Additional

Accounts Receivable - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Receivables [Abstract]	'	'	'
Expected invoiced period for billable amounts	'12 months	'	'
Contract receivables	$135.80	$137.50	$138.90
Percentage of contract receivables	79.00%	78.00%	77.00%
Revenue in excess of billings on uncompleted contracts	68.4	74.1	85.4
Revenue from customer-requested work	17.8	14.6	19
Threshold of contractual operating cycles	'1 year	'1 year	'
Exception of invoice and collect unbilled receivables	$18.60	$19.60	'

Property_Plant_and_Equipment_P

Property, Plant and Equipment - Property, Plant and Equipment (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Property Plant And Equipment [Abstract]	'	'	'
Leasehold improvements	$12,603	$12,984	$12,168
Equipment and software	35,314	35,203	35,562
Total cost	47,917	48,187	47,730
Less: accumulated depreciation and amortization	-38,847	-38,519	-37,125
Net Property, Plant and Equipment	$9,070	$9,668	$10,605

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Property Plant And Equipment [Abstract]	'	'	'	'	'
Depreciation and leasehold amortization expense for fixed assets	$778	$788	$3,300	$4,300	$4,400

Goodwill_Additional_Informatio

Goodwill - Additional Information (Detail) (USD $)	3 Months Ended			6 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
	Segment				Segment
	Reporting_Unit
Goodwill [Line Items]	'	'	'	'	'	'	'
Goodwill	$398,921,000	$398,921,000	'	$398,921,000	$398,921,000	$398,921,000	'
Changes to goodwill during period	'	'	'	'	0	0	0
Number of segments	1	'	'	'	1	'	'
Reduced number of reporting units	2	'	'	'	'	'	'
Contract revenue	185,380,000	'	204,329,000	'	848,972,000	817,204,000	787,314,000
Contract backlog	'	'	'	'	'Contract backlog was approximately 2.6 times trailing twelve month revenue	'Contract backlog was approximately 2.9 times trailing twelve month revenue	'
Projected revenue and EBITDA and discounted median market multiples	'	'	'	'	30.00%	'	'
Weighted average cost of capital rate	'	'	'	'	13.00%	12.50%	'
Hypothetical increase or decrease in the weighted average cost of capital rate	'	'	'	'	10.00%	'	'
Decrease in estimated enterprise value	'	'	'	'	5.70%	'	'
Increase in estimated enterprise value	'	'	'	'	6.90%	'	'
Percentage of value based on EBITDA multiples from mergers and acquisitions to discounted cash flow enterprise value	'	'	'	'	26.00%	'	'
Additional customer contract funding	'	'	'	840,000,000	840,000,000	'	'
Goodwill impairment	0	0	'	'	0	'	'
Estimated fair value of outstanding debt increased	'	'	'	'	10.00%	'	'
Percentage of outstanding common stock declined	'	'	'	'	50.00%	'	'
Hypothetical decrease in fair value of goodwill	'	'	'	'	10.00%	'	'
Intersegment Elimination [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Contract revenue	292,000	'	'	'	292,000	703,000	'
Minimum [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Market multiples for trailing twelve month EBITDA	'	'	'	'	7.6	5.6	'
Market multiples for trailing twelve month revenue	'	'	'	'	0.3	0.3	'
Projected revenue and EBITDA and discounted median market multiples	'	'	'	'	'	14.00%	'
Goodwill for impairment, near-term growth values	'	'	'	'	0.00%	0.00%	'
Goodwill for impairment, longer-term out year forecasts	'	'	'	'	0.00%	0.00%	'
Maximum [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Market multiples for trailing twelve month EBITDA	'	'	'	'	18.2	18.2	'
Market multiples for trailing twelve month revenue	'	'	'	'	3.01	3.02	'
Projected revenue and EBITDA and discounted median market multiples	'	'	'	'	'	40.00%	'
Goodwill for impairment, near-term growth values	'	'	'	'	4.00%	1.00%	'
Goodwill for impairment, longer-term out year forecasts	'	'	'	'	4.00%	2.00%	'
Estimated discounted future cash flows decreased	'	'	'	'	1.00%	'	'
Median [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Market multiples for trailing twelve month EBITDA	'	'	'	'	13.4	12.8	'
Market multiples for trailing twelve month revenue	'	'	'	'	1.36	1.32	'
TEOSS [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Goodwill	201,900,000	201,900,000	'	201,900,000	201,900,000	'	'
Contract revenue	477,000,000	'	'	'	477,000,000	435,000,000	'
EISS [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Goodwill	197,000,000	197,000,000	'	197,000,000	197,000,000	'	'
Contract revenue	$371,000,000	'	'	'	$371,000,000	$386,000,000	'

Intangible_Assets_Intangible_A

Intangible Assets - Intangible Assets (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'	'
Intangible Assets, Gross	$114,817	$114,817	$114,817
Intangible Assets, Accumulated Amortization	-113,082	-112,777	-109,575
Intangible Assets, Net	1,735	2,040	5,242
Purchased Contracts [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Intangible Assets, Gross	111,635	111,635	111,635
Intangible Assets, Accumulated Amortization	-110,015	-109,795	-106,935
Intangible Assets, Net	1,620	1,840	4,700
Internal Use Software and Engineering Designs [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Intangible Assets, Gross	3,182	3,182	3,182
Intangible Assets, Accumulated Amortization	-3,067	-2,982	-2,640
Intangible Assets, Net	$115	$200	$542

Intangible_Assets_Additional_I

Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Goodwill And Intangible Assets Disclosure [Abstract]	'	'	'	'	'
Weighted-average remaining amortization period of intangible assets	'18 months	'	'18 months	'	'
Amortization expense	$305,000	$1,500,000	$3,200,000	$6,500,000	$7,000,000

Intangible_Assets_Estimated_Ag

Intangible Assets - Estimated Aggregate Amortization Expense (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Goodwill And Intangible Assets Disclosure [Abstract]	'	'	'
2014 (for the remainder of the fiscal year)	$773	'	'
2015	737	1,079	'
2016	141	736	'
2017	51	141	'
2018	33	51	'
2019	'	33	'
Thereafter	'	'	'
Intangible Assets, Net	$1,735	$2,040	$5,242

Current_and_LongTerm_Debt_Addi

Current and Long-Term Debt - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Mar. 31, 2010

Mar. 22, 2010

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Mar. 22, 2010

Mar. 22, 2010

Mar. 31, 2010

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2013

Sep. 30, 2013

Jul. 31, 2013

Jun. 30, 2013

Jun. 30, 2011

Nov. 30, 2010

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Feb. 28, 2007

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Letters of Credit [Member]

Letters of Credit [Member]

Eurodollar Base Rate [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

PIK Interest Notes Issued [Member]

PIK Interest Notes Issued [Member]

Letters of Credit [Member]

Short-Term Swing Line Loans [Member]

Short-Term Swing Line Loans [Member]

Minimum [Member]

Minimum [Member]

Letters of Credit [Member]

Letters of Credit [Member]

Eurodollar Interest Rate [Member]

Eurodollar Interest Rate [Member]

Alternate Base Rate [Member]

Alternate Base Rate [Member]

Unit

Unit

Unit

Maximum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility outstanding

'

'

'

'

'

'

'

'

'

'

$35,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Face value of outstanding notes

310,000,000

'

310,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

333,086,000

329,788,000

323,293,000

'

'

'

'

'

'

235,000,000

235,000,000

245,000,000

'

'

'

'

23,100,000

19,800,000

Debt instrument, maturity date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1-Nov-14

1-Nov-14

'

'

'

'

'

'

'

1-Feb-15

1-Feb-15

'

'

'

'

'

'

'

Expiration date of agreement

'

'

'

'

'

'

'

'

'

'

22-Aug-14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Credit limit, maximum capacity

30,000,000

'

'

'

'

'

'

'

'

'

'

'

5,000,000

5,000,000

'

'

35,000,000

35,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility

'

'

'

'

'

'

'

4,000,000

4,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate

'

'

'

'

'

'

'

'

'

6.00%

'

'

'

'

8.50%

8.50%

'

'

2.50%

2.50%

3.50%

3.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate spread basis points

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.00%

6.00%

5.00%

5.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate description

'

'

'

'

'

'

'

'

'

'

'The minimum Eurodollar interest rate is 2.5% plus 600 basis points

'The minimum Eurodollar interest rate is 2.5% plus 600 basis points

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility alternate base rate description

'

'

'

'

'

'

'

'

'

'

'The minimum alternate base rate is 3.5% plus 500 basis points

'The minimum alternate base rate is 3.5% plus 500 basis points

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitment fee, basis points

1.75%

'

1.75%

'

'

'

'

'

'

0.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitment fee, amount

125,000

142,000

533,000

559,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility restrictive covenants EBITDA amount

65,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility restrictive covenants, period

'Through August 22, 2014

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of loan by syndicate lenders

'

'

'

'

'

'

'

'

'

'

50.00%

50.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital expenditures covenants

'

'

'

'

'

'

'

'

'

'

8,000,000

8,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Incurrence of a civil or criminal liability

5,000,000

'

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net proceeds from an underwritten public offering

'

'

'

'

'

'

'

'

'

'

35,000,000

35,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ownership percentage for control

'

'

'

'

'

'

'

'

'

'

51.00%

51.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding equity interests

'

'

'

'

'

'

'

'

'

'

37.50%

37.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Private units issued, value

'

'

'

'

'

310,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

250,000,000

'

'

'

'

Secured notes and warrants issued

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

310,000

310,000

310,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument interest rate stated percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

12.00%

12.00%

12.00%

'

'

'

'

'

'

'

10.25%

10.25%

'

'

10.25%

'

'

'

'

Common shares called by each warrant

'

'

'

'

'

'

1.9439

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.9439

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Each note face value

'

'

'

'

'

'

1,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument cash interest rate percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument paid-in-kind interest rate percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest on overdue principal

13.00%

'

13.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11.25%

11.25%

'

'

'

'

'

'

'

Ratio of trailing twelve month adjusted EBITDA to trailing twelve month consolidated interest expense, requirement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'Greater than 2.0 to 1.0

'Greater than 2.0 to 1.0

'

'

'

'

'

'

'

'Greater than 2.0 to 1.0

'Greater than 2.0 to 1.0

'

'

'

'

'

'

'

Ratio of trailing twelve month Adjusted EBITDA to trailing twelve month consolidated interest expense, actual

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'0.89 to 1.0

'0.91 to 1.0

'0.93 to 1.0

'

'

'

'

'

'

'0.92 to 1.0

'0.91 to 1.0

'0.93 to 1.0

'

'

'

'

'

'

Adjusted EBITDA to consolidated interest expense ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.92

0.91

'

'

'

'

'

'

'

0.92

0.91

0.93

'

'

'

'

'

'

Our ratio of adjusted EBITDA

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

67,700,000

69,000,000

69,300,000

'

'

'

'

'

'

69,600,000

69,000,000

69,300,000

'

'

'

'

'

'

Consolidated interest expense

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75,700,000

75,700,000

74,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt covenant amount debt pursuant to certain agreements

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

25,000,000

'

'

'

'

'

'

'

360,000,000

360,000,000

'

'

'

'

'

'

'

Debt covenants amount for capital expenditures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

25,000,000

'

'

'

'

'

'

'

25,000,000

25,000,000

'

'

'

'

'

'

'

Debt covenants amount for capital expenditures as percentage of assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.50%

2.50%

'

'

'

'

'

'

'

2.50%

2.50%

'

'

'

'

'

'

'

Debt covenant amount permitted subordinated debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

35,000,000

35,000,000

'

'

'

'

'

'

'

Other debt covenants amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20,000,000

20,000,000

'

'

'

'

'

'

'

35,000,000

35,000,000

'

'

'

'

'

'

'

Debt covenant exemption

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'If Adjusted EBITDA is at least two times Consolidated Interest Expense

'If Adjusted EBITDA is at least two times Consolidated Interest Expense

'

'

'

'

'

'

'

'If Adjusted EBITDA is at least two times Consolidated Interest Expense

'If Adjusted EBITDA is at least two times Consolidated Interest Expense

'

'

'

'

'

'

'

Debt covenant above required threshold exemption

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0

'Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0

'

'

'

'

'

'

'

'Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0, we may make or pay

'Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0, we may make or pay

'

'

'

'

'

'

'

Long-term incentive plan payments annual cap

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,000,000

3,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Acquisition or retirement for value debt covenants amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,000,000

10,000,000

'

'

Other payments covenant amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,000,000

10,000,000

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

Debt default acceleration limit for other debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

Judgment for payment against company or any material subsidiary

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

Period of judgment for payment against company or any material subsidiary

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'60 days

'60 days

'

'

'

'

'

'

'

'60 days

'60 days

'

'

'

'

'

'

'

Unsecured debt redemption price as percentage of principal in case of change in control

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

101.00%

101.00%

'

'

'

'

'

'

'

101.00%

101.00%

'

'

'

'

'

'

'

Minimum voting power required for change in control purpose

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

35.00%

35.00%

'

'

'

'

'

'

'

35.00%

35.00%

'

'

'

'

'

'

'

Debt instrument redemption occasion

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'From April 1, 2013 through September 30, 2013

'From April 1, 2013 through September 30, 2013

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument redemption price percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

105.00%

105.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument redemption price percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

103.00%

103.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument repurchase amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

15,000,000

15,000,000

'

'

'

'

'

'

'

Debt instrument repurchase amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,000,000

5,000,000

3,000,000

2,000,000

'

'

'

'

'

'

'

'

'

Gains (losses) on extinguishment of debt

'

'

3,913,000

'

939,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,900,000

0

939,000

'

'

'

'

'

Minimum adjusted EBITDA to consolidated interest expense ratio to maintain under covenants

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

2

'

'

'

'

'

'

'

Consolidated interest expense

18,948,000

18,919,000

75,700,000

74,934,000

73,919,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75,700,000

75,700,000

74,900,000

'

'

'

'

'

'

Debt covenant amount permitted transactions with ESOP

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

25,000,000

'

'

'

'

'

'

'

Senior notes refinancing cost

$600,000,000

'

$600,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current_and_LongTerm_Debt_Inte

Current and Long-Term Debt - Interest Payable (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Interest Expense [Line Items]	'	'	'
Interest payable	$15,590	$17,758	$17,658
Secured Notes and Warrants [Member]	'	'	'
Interest Expense [Line Items]	'	'	'
Interest payable	5,551	13,741	13,470
Unsecured Notes [Member]	'	'	'
Interest Expense [Line Items]	'	'	'
Interest payable	$10,039	$4,017	$4,188

Current_and_LongTerm_Debt_Prin

Current and Long-Term Debt - Principal Repayments (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'
Total Principal Payments in Rolling Year One	'	'
Total Principal Payments in Rolling Year Two	574,788	574,788
Total Principal Payments	574,788	574,788
Secured Notes and Warrants [Member]	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'
Total Principal Payments in Rolling Year One	'	'
Total Principal Payments in Rolling Year Two	339,788	339,788
Total Principal Payments	339,788	339,788
Unsecured Notes [Member]	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'
Total Principal Payments in Rolling Year One	'	'
Total Principal Payments in Rolling Year Two	235,000	235,000
Total Principal Payments	$235,000	$235,000

Current_and_LongTerm_Debt_Prin1

Current and Long-Term Debt - Principal Repayments (Parenthetical) (Detail) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2010	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
Secured Notes	'	$326,313,000	'	'
Face value of outstanding notes	'	310,000,000	310,000,000	'
PIK notes issued and PIK interest accrued	'	'	322,286,000	306,502,000
Secured Notes and Warrants [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
Amount originally issued	310,000,000	'	'	'
Increases in secured note principal (PIK interest)	29,800,000	'	'	'
Secured Notes	'	326,314,000	322,286,000	'
Face value of outstanding notes	'	333,086,000	329,788,000	323,293,000
Unamortized debt issue costs	'	7,883,000	10,250,000	19,483,000
Debt issue costs	'	7,700,000	7,700,000	'
Debt issuance third-party costs	'	13,500,000	13,500,000	'
Warrants not settleable in cash fair value disclosure	'	20,800,000	20,800,000	'
Maturity of debt	'	'2014-11	'2014-11	'
Unsecured Notes [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
Face value of outstanding notes	'	235,000,000	235,000,000	245,000,000
Unamortized debt issue costs	'	962,000	1,168,000	2,077,000
Debt issue costs	'	7,100,000	7,100,000	'
Maturity of debt	'	'2015-02	'2015-02	'
Debt instrument repurchase amount	'	15,000,000	15,000,000	'
PIK Notes [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
PIK notes issued and PIK interest accrued	'	23,100,000	19,800,000	'
PIK Interest [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
PIK notes issued and PIK interest accrued	'	$1,100,000	$2,700,000	'

Fair_Value_Measurement_Face_Va

Fair Value Measurement - Face Value, Net Carrying Value and Fair Value of Secured and Unsecured Notes (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	$310,000,000	$310,000,000	'
Carrying value	326,313,000	'	'
Carrying value	234,038,000	233,832,000	242,923,000
Unsecured Notes [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	235,000,000	235,000,000	245,000,000
Face value of notes outstanding and notes to be issued	235,000,000	235,000,000	245,000,000
Less: unamortized debt issue costs	-962,000	-1,168,000	-2,077,000
Carrying value	234,038,000	233,832,000	242,923,000
Unsecured Notes [Member] | Original Notes [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	235,000,000	235,000,000	245,000,000
Secured Notes and Warrants [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	333,086,000	329,788,000	323,293,000
Face value of notes outstanding and notes to be issued	334,197,000	332,536,000	325,985,000
Less: unamortized debt issue costs	-7,883,000	-10,250,000	-19,483,000
Carrying value	326,314,000	322,286,000	'
Carrying value	'	322,286,000	306,502,000
Secured Notes and Warrants [Member] | Original Notes [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	310,000,000	310,000,000	310,000,000
Secured Notes and Warrants [Member] | PIK Interest Notes Issued [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	23,086,000	19,788,000	13,293,000
PIK interest notes to be issued	1,111,000	2,748,000	2,692,000
Fair Value, Inputs, Level 2 [Member] | Unsecured Notes [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Fair value of outstanding notes	165,894,000	151,928,000	141,605,000
Fair Value, Inputs, Level 2 [Member] | Secured Notes and Warrants [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Fair value of outstanding notes	$339,681,000	$335,295,000	$303,598,000

Secured_Note_Common_Stock_Warr1

Secured Note Common Stock Warrants - Additional Information (Detail) (USD $)	Mar. 22, 2010	Mar. 22, 2010	Mar. 22, 2010	Dec. 31, 2013	Sep. 30, 2013
		Capital Units [Member]	Capital Units [Member]	Warrant [Member]	Warrant [Member]
		Unit	Unit
Class of Warrant or Right [Line Items]	'	'	'	'	'
Secured notes and warrants issued	'	310,000	310,000	'	'
Each secured note face value	$1,000	'	'	'	'
Common shares called by each warrant	1.9439	'	'	'	'
Common stock purchased	602,614	'	'	'	'
Exercise price of warrants	0.01	'	'	'	'
Expiry date	15-Mar-17	'	'	15-Mar-17	15-Mar-17
Warrant exercisable date	'	'	'	22-Mar-11	22-Mar-11
Initial fair value of the secured note warrants	'	'	'	$20,800,000	$20,800,000
Estimated fair value share price	'	'	'	$34.50	$34.50

Leases_Future_Minimum_Lease_Pa

Leases - Future Minimum Lease Payments (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified
Leases [Abstract]	'	'
2014 (for the remainder of fiscal year)	$19,497	'
2015	25,076	26,009
2016	21,183	24,875
2017	17,783	21,041
2018	14,931	17,804
2019	6,162	14,931
And thereafter	12,947	19,109
Gross lease payments	117,579	123,769
Less: non-cancelable subtenant receipts	-1,593	-1,711
Net lease payments	$115,986	$122,058

Leases_Composition_of_Total_Re

Leases - Composition of Total Rent Expense (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Leases [Abstract]	'	'	'	'	'
Minimum rentals	$5,515	$5,301	$21,530	$20,639	$21,992
Less: Sublease rental income	-143	-104	-600	-156	-1,610
Total rent expense, net	$5,372	$5,197	$20,930	$20,483	$20,382

ESOP_Expense_Additional_Inform

ESOP Expense - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2013	Sep. 30, 2013	Mar. 31, 2013
						ESOP [Member]	ESOP [Member]	ESOP [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]	'	'	'	'	'	'	'	'
ESOP plan scheme	'The Company matches the first 3% and one-half of the next 2% of eligible employee salary deferrals by contributing shares of Alion common stock to the ESOP Trust on March 31 and September 30 each year.	'	'The Company matches the first 3% and one-half of the next 2% of eligible employee salary deferrals by contributing shares of Alion common stock to the ESOP Trust on March 31 and September 30 each year.	'	'	'	'	'
Percentage of employer contribution as a percentage of employee contribution deferral	3.00%	'	3.00%	'	'	'	'	'
Percentage of salary	2.00%	'	2.00%	'	'	'	'	'
Recognized ESOP expense	$3,600,000	$3,400,000	$13,800,000	$13,800,000	$13,200,000	'	'	'
Employee funds used for purchase of common stock	$930,000	'	$930,000	'	'	'	'	'
Estimated fair value of share price	'	'	'	'	'	$8.10	$8.10	$16.25

Long_Term_Incentive_Compensati1

Long Term Incentive Compensation Plan - Additional Information (Detail) (Long Term Incentive Compensation Plan [Member], USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Long Term Incentive Compensation Plan [Member]	'	'	'	'	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'	'	'	'	'
Grant value, minimum	50.00%	'	50.00%	'	'
Grant value, maximum	150.00%	'	150.00%	'	'
Incentive compensation expense	$804	$742	$2,300	$1,400	$2,800

Stock_Based_Compensation_Addit

Stock Based Compensation - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Stock Based Compensation [Member]

Stock Based Compensation [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Phantom Stock Plan [Member]

Phantom Stock Plan [Member]

Performance Shares [Member]

Performance Shares [Member]

Retention Phantom Stock Plan [Member]

Retention Phantom Stock Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Vested awards

'

'

'

'

'

'

'

'Awards vest ratably over four years with payment following the grant date fifth anniversary

'Awards vest ratably over four years with payment following the grant date fifth anniversary

'

'

'

'

'

'

Awards vesting period

'

'

'

'

'

'

'

'4 years

'4 years

'

'

'

'

'

'

Expiration period of grants with no intrinsic value

'

'

'

'

'

'

'

'5 years

'5 years

'

'

'

'

'

'

Expiration of plan

'

'

'

'

'

'

'

'2016-11

'2016-11

'

'

'

'

'

'

Outstanding stock appreciation rights

'

'

'

'

'

'

'

587,000

709,000

'

'

'

'

'

'

Weighted average grant date fair value

'

'

'

'

'

'

'

$22.52

$24.96

'

'

'

'

'

'

Grants outstanding

'

'

'

'

'

'

'

'

'

0

0

0

0

0

0

Recognized compensation expense

$805

$752

$2,065

$1,310

$2,655

$0

$10

'

'

'

'

'

'

'

'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Deferred Income Tax Assets And Liabilities [Line Items]	'	'	'	'	'
Goodwill-related deferred tax expense and liabilities	$1,700,000	$1,700,000	'	'	'
Current income tax expense recognized	'	'	3,000	'	'
Effective tax rate	-10.40%	-18.80%	-23.60%	-20.20%	-18.60%
Deferred tax assets benefit percentage	50.00%	'	50.00%	'	'
India [Member]	'	'	'	'	'
Deferred Income Tax Assets And Liabilities [Line Items]	'	'	'	'	'
Current income tax expense recognized	$2,000	$0	$2,000	'	'

Income_Taxes_Summary_of_Net_De

Income Taxes - Summary of Net Deferred Tax Liability (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]	'	'	'
Current deferred tax asset	$7,355	$9,228	'
Noncurrent deferred tax asset	98,007	87,812	'
Valuation allowance	-105,362	-97,040	-78,414
Noncurrent deferred tax liability	-59,873	-58,130	-51,156
Net deferred tax liability	($59,873)	($58,130)	($51,156)

Segment_Information_Additional

Segment Information - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Receivables From Major Customers [Line Items]	'	'	'	'	'
Number of segments	1	'	1	'	'
Sales [Member] | U.S. Government Prime Contracts [Member]	'	'	'	'	'
Receivables From Major Customers [Line Items]	'	'	'	'	'
Percentage revenue from government prime contracts to total contract revenue	87.00%	89.00%	89.00%	86.00%	84.00%

GuarantorNonGuarantor_Unaudite2

Guarantor/Non-Guarantor Unaudited Condensed Consolidated Financial Information - Condensed Consolidating Balance Sheet (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Sep. 30, 2010
In Thousands, unless otherwise specified
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	$4,687	$25,613	'	'	$19,461	$27,227	'	'	'	$20,818	$26,695
Accounts receivable, net	168,963	172,604	'	'	'	175,293	'	'	'	'	'
Receivable due from ESOP Trust	'	930	'	'	'	1,129	'	'	'	'	'
Prepaid expenses and other current assets	5,648	4,483	'	'	'	5,448	'	'	'	'	'
Total current assets	179,298	203,630	211,464	223,550	203,722	209,097	211,266	200,703	205,819	'	'
Property, plant and equipment, net	9,070	9,668	'	'	'	10,605	'	'	'	'	'
Intangible assets, net	1,735	2,040	'	'	'	5,242	'	'	'	'	'
Goodwill	398,921	398,921	'	'	'	398,921	'	'	'	'	'
Other assets	10,368	10,367	'	'	'	11,431	'	'	'	'	'
Total assets	599,392	624,626	'	'	'	635,296	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Interest payable	15,590	17,758	'	'	'	17,658	'	'	'	'	'
Secured Notes	326,313	'	'	'	'	'	'	'	'	'	'
Trade accounts payable	59,536	61,622	'	'	'	44,793	'	'	'	'	'
Accrued liabilities	36,909	39,393	'	'	'	52,460	'	'	'	'	'
Accrued payroll and related liabilities	31,733	37,954	'	'	'	39,926	'	'	'	'	'
Billings in excess of costs revenue earned	4,562	4,334	'	'	'	2,666	'	'	'	'	'
Total current liabilities	474,643	161,061	167,253	171,700	157,168	157,503	166,520	152,200	166,226	'	'
Secured Notes	'	322,286	'	'	'	306,502	'	'	'	'	'
Unsecured Notes	234,038	233,832	'	'	'	242,923	'	'	'	'	'
Accrued compensation and benefits, excluding current portion	5,998	5,736	'	'	'	5,905	'	'	'	'	'
Non-current portion of lease obligations	12,540	12,821	'	'	'	12,364	'	'	'	'	'
Deferred income taxes	59,873	58,130	'	'	'	51,156	'	'	'	'	'
Redeemable common stock	61,896	61,895	'	'	'	110,740	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Common stock warrants	20,785	20,785	'	'	'	20,785	'	'	'	'	'
Accumulated other comprehensive loss	130	130	'	'	'	-149	'	'	'	'	'
Accumulated surplus (deficit)	-270,511	-252,050	'	'	'	-272,433	'	'	'	'	'
Total liabilities, redeemable common stock and accumulated deficit	599,392	624,626	'	'	'	'	'	'	'	'	'
Ownership in subsidiary percentage	100.00%	100.00%	'	'	'	'	'	'	'	'	'
Parent [Member]	'	'	'	'	'	'	'	'	'	'	'
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	4,670	25,617	'	'	19,485	27,271	'	'	'	20,844	26,770
Accounts receivable, net	166,283	169,304	'	'	'	172,365	'	'	'	'	'
Receivable due from ESOP Trust	'	930	'	'	'	1,129	'	'	'	'	'
Prepaid expenses and other current assets	5,587	4,449	'	'	'	5,378	'	'	'	'	'
Total current assets	176,540	200,300	'	'	'	206,143	'	'	'	'	'
Property, plant and equipment, net	8,552	9,139	'	'	'	10,064	'	'	'	'	'
Intangible assets, net	1,735	2,040	'	'	'	5,242	'	'	'	'	'
Goodwill	398,921	398,921	'	'	'	398,921	'	'	'	'	'
Investment in subsidiaries	28,710	28,420	'	'	'	27,994	'	'	'	'	'
Intercompany receivables	1,963	1,906	'	'	'	1,438	'	'	'	'	'
Other assets	10,364	10,363	'	'	'	11,427	'	'	'	'	'
Total assets	626,785	651,089	'	'	'	661,229	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Interest payable	15,590	17,758	'	'	'	17,658	'	'	'	'	'
Secured Notes	326,313	'	'	'	'	'	'	'	'	'	'
Trade accounts payable	59,465	61,563	'	'	'	44,582	'	'	'	'	'
Accrued liabilities	36,710	39,169	'	'	'	52,265	'	'	'	'	'
Accrued payroll and related liabilities	31,399	37,404	'	'	'	39,305	'	'	'	'	'
Billings in excess of costs revenue earned	4,452	4,250	'	'	'	2,656	'	'	'	'	'
Total current liabilities	473,929	160,144	'	'	'	156,466	'	'	'	'	'
Intercompany payables	28,537	27,826	'	'	'	27,476	'	'	'	'	'
Secured Notes	'	322,286	'	'	'	306,502	'	'	'	'	'
Unsecured Notes	234,038	233,832	'	'	'	242,923	'	'	'	'	'
Accrued compensation and benefits, excluding current portion	5,998	5,736	'	'	'	5,905	'	'	'	'	'
Non-current portion of lease obligations	12,110	12,374	'	'	'	11,858	'	'	'	'	'
Deferred income taxes	59,873	58,130	'	'	'	51,156	'	'	'	'	'
Redeemable common stock	61,896	61,895	'	'	'	110,740	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Common stock warrants	20,785	20,785	'	'	'	20,785	'	'	'	'	'
Accumulated other comprehensive loss	130	130	'	'	'	-149	'	'	'	'	'
Accumulated surplus (deficit)	-270,511	-252,049	'	'	'	-272,433	'	'	'	'	'
Total liabilities, redeemable common stock and accumulated deficit	626,785	651,089	'	'	'	'	'	'	'	'	'
Guarantor Companies [Member]	'	'	'	'	'	'	'	'	'	'	'
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	-10	-24	'	'	-29	-44	'	'	'	-26	-74
Accounts receivable, net	2,038	2,735	'	'	'	2,783	'	'	'	'	'
Prepaid expenses and other current assets	36	188	'	'	'	70	'	'	'	'	'
Total current assets	2,064	2,899	'	'	'	2,809	'	'	'	'	'
Property, plant and equipment, net	515	525	'	'	'	529	'	'	'	'	'
Intercompany receivables	28,536	27,828	'	'	'	27,475	'	'	'	'	'
Total assets	31,115	31,252	'	'	'	30,813	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Trade accounts payable	40	58	'	'	'	201	'	'	'	'	'
Accrued liabilities	96	144	'	'	'	190	'	'	'	'	'
Accrued payroll and related liabilities	303	517	'	'	'	589	'	'	'	'	'
Billings in excess of costs revenue earned	110	84	'	'	'	6	'	'	'	'	'
Total current liabilities	549	803	'	'	'	986	'	'	'	'	'
Intercompany payables	'	153	'	'	'	'	'	'	'	'	'
Non-current portion of lease obligations	430	447	'	'	'	506	'	'	'	'	'
Common stock of subsidiaries	4,084	4,084	'	'	'	4,084	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Accumulated surplus (deficit)	26,052	25,765	'	'	'	25,237	'	'	'	'	'
Total liabilities, redeemable common stock and accumulated deficit	31,115	31,252	'	'	'	'	'	'	'	'	'
Non-Guarantor Companies [Member]	'	'	'	'	'	'	'	'	'	'	'
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	27	20	'	'	5	'	'	'	'	'	-1
Accounts receivable, net	642	565	'	'	'	145	'	'	'	'	'
Prepaid expenses and other current assets	25	-154	'	'	'	'	'	'	'	'	'
Total current assets	694	431	'	'	'	145	'	'	'	'	'
Property, plant and equipment, net	3	4	'	'	'	12	'	'	'	'	'
Other assets	4	4	'	'	'	4	'	'	'	'	'
Total assets	701	439	'	'	'	161	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Trade accounts payable	31	1	'	'	'	10	'	'	'	'	'
Accrued liabilities	103	80	'	'	'	5	'	'	'	'	'
Accrued payroll and related liabilities	31	33	'	'	'	32	'	'	'	'	'
Billings in excess of costs revenue earned	'	'	'	'	'	4	'	'	'	'	'
Total current liabilities	165	114	'	'	'	51	'	'	'	'	'
Intercompany payables	1,962	1,754	'	'	'	1,437	'	'	'	'	'
Common stock of subsidiaries	9	9	'	'	'	'	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Accumulated surplus (deficit)	-1,435	-1,438	'	'	'	-1,327	'	'	'	'	'
Total liabilities, redeemable common stock and accumulated deficit	701	439	'	'	'	'	'	'	'	'	'
Eliminations [Member]	'	'	'	'	'	'	'	'	'	'	'
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Investment in subsidiaries	-28,710	-28,420	'	'	'	-27,994	'	'	'	'	'
Intercompany receivables	-30,499	-29,734	'	'	'	-28,913	'	'	'	'	'
Total assets	-59,209	-58,154	'	'	'	-56,907	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Intercompany payables	-30,499	-29,733	'	'	'	-28,913	'	'	'	'	'
Common stock of subsidiaries	-4,093	-4,093	'	'	'	-4,084	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Accumulated surplus (deficit)	-24,617	-24,328	'	'	'	-23,910	'	'	'	'	'
Total liabilities, redeemable common stock and accumulated deficit	($59,209)	($58,154)	'	'	'	'	'	'	'	'	'

GuarantorNonGuarantor_Unaudite3

Guarantor/Non-Guarantor Unaudited Condensed Consolidated Financial Information - Condensed Consolidating Statement of Operations and Comprehensive Loss (Detail) (USD $)

3 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Schedule Of Condensed Consolidating Statement Of Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

$185,380

'

'

'

$204,329

'

'

'

'

$848,972

$817,204

$787,314

Direct contract expense

145,275

'

'

'

160,635

'

'

'

'

669,504

632,831

603,481

Gross profit

40,105

42,822

46,633

46,319

43,694

47,673

46,472

46,681

43,547

179,468

184,373

183,833

Operating expenses

18,864

'

'

'

22,250

'

'

'

'

84,128

91,494

83,035

General and administrative

18,993

'

'

'

11,804

'

'

'

'

53,139

52,441

65,305

Operating income (loss)

2,248

'

'

'

9,640

'

'

'

'

42,201

40,438

35,493

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Interest income

11

'

'

'

17

'

'

'

'

55

78

45

Interest expense

-18,948

'

'

'

-18,919

'

'

'

'

-75,700

-74,934

-73,919

Other

-28

'

'

'

-15

'

'

'

'

-84

-55

32

Total other (expense) income

-18,965

'

'

'

-18,917

'

'

'

'

-71,816

-74,911

-72,903

(Loss) income before taxes

-16,717

'

'

'

-9,277

'

'

'

'

-29,615

-34,473

-37,410

Income tax expense

-1,745

'

'

'

-1,744

'

'

'

'

-6,977

-6,974

-6,974

Net income (loss)

-18,462

-9,353

-7,087

-9,131

-11,021

-9,526

-8,866

-10,245

-12,810

-36,592

-41,447

-44,384

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Postretirement actuarial gains

'

'

'

'

'

'

'

'

'

279

26

55

Comprehensive income (loss)

-18,462

'

'

'

-11,021

'

'

'

'

-36,313

-41,421

-44,329

Parent [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Schedule Of Condensed Consolidating Statement Of Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

183,384

'

'

'

202,057

'

'

'

'

839,608

802,664

769,467

Direct contract expense

144,060

'

'

'

159,162

'

'

'

'

663,380

624,788

593,600

Gross profit

39,324

'

'

'

42,895

'

'

'

'

176,228

177,876

175,867

Operating expenses

18,385

'

'

'

21,621

'

'

'

'

81,838

88,736

79,871

General and administrative

18,983

'

'

'

11,734

'

'

'

'

52,491

52,123

64,374

Operating income (loss)

1,956

'

'

'

9,540

'

'

'

'

41,899

37,017

31,622

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Interest income

11

'

'

'

17

'

'

'

'

55

78

45

Interest expense

-18,948

'

'

'

-18,919

'

'

'

'

-75,700

-74,934

-73,919

Other

-28

'

'

'

-15

'

'

'

'

-200

-63

-535

Equity in net income (loss) of subsidiaries

292

'

'

'

100

'

'

'

'

418

3,429

4,438

Total other (expense) income

-18,673

'

'

'

-18,817

'

'

'

'

-71,514

-71,490

-69,032

(Loss) income before taxes

-16,717

'

'

'

-9,277

'

'

'

'

-29,615

-34,473

-37,410

Income tax expense

-1,745

'

'

'

-1,744

'

'

'

'

-6,977

-6,974

-6,974

Net income (loss)

-18,462

'

'

'

-11,021

'

'

'

'

-36,592

-41,447

-44,384

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Postretirement actuarial gains

'

'

'

'

'

'

'

'

'

279

26

55

Comprehensive income (loss)

-18,462

'

'

'

-11,021

'

'

'

'

-36,313

-41,421

-44,329

Guarantor Companies [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Schedule Of Condensed Consolidating Statement Of Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

1,771

'

'

'

2,218

'

'

'

'

8,627

14,015

17,025

Direct contract expense

1,091

'

'

'

1,337

'

'

'

'

5,638

7,743

9,333

Gross profit

680

'

'

'

881

'

'

'

'

2,989

6,272

7,692

Operating expenses

392

'

'

'

560

'

'

'

'

1,972

2,531

3,076

General and administrative

1

'

'

'

49

'

'

'

'

604

156

620

Operating income (loss)

287

'

'

'

272

'

'

'

'

413

3,585

3,996

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Other

'

'

'

'

'

'

'

'

'

116

9

568

Total other (expense) income

'

'

'

'

'

'

'

'

'

116

9

568

(Loss) income before taxes

287

'

'

'

272

'

'

'

'

529

3,594

4,564

Net income (loss)

287

'

'

'

272

'

'

'

'

529

3,594

4,564

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Postretirement actuarial gains

'

'

'

'

'

'

'

'

'

'

'

'

Comprehensive income (loss)

287

'

'

'

272

'

'

'

'

529

3,594

4,564

Non-Guarantor Companies [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Schedule Of Condensed Consolidating Statement Of Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

225

'

'

'

54

'

'

'

'

737

525

822

Direct contract expense

124

'

'

'

136

'

'

'

'

486

300

548

Gross profit

101

'

'

'

-82

'

'

'

'

251

225

274

Operating expenses

87

'

'

'

69

'

'

'

'

318

227

88

General and administrative

9

'

'

'

21

'

'

'

'

44

162

311

Operating income (loss)

5

'

'

'

-172

'

'

'

'

-111

-164

-125

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Other

'

'

'

'

'

'

'

'

'

'

-1

-1

Total other (expense) income

'

'

'

'

'

'

'

'

'

'

-1

-1

(Loss) income before taxes

5

'

'

'

-172

'

'

'

'

-111

-165

-126

Net income (loss)

5

'

'

'

-172

'

'

'

'

-111

-165

-126

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Postretirement actuarial gains

'

'

'

'

'

'

'

'

'

'

'

'

Comprehensive income (loss)

5

'

'

'

-172

'

'

'

'

-111

-165

-126

Eliminations [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Equity in net income (loss) of subsidiaries

-292

'

'

'

-100

'

'

'

'

-418

-3,429

-4,438

Total other (expense) income

-292

'

'

'

-100

'

'

'

'

-418

-3,429

-4,438

(Loss) income before taxes

-292

'

'

'

-100

'

'

'

'

-418

-3,429

-4,438

Net income (loss)

-292

'

'

'

-100

'

'

'

'

-418

-3,429

-4,438

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Postretirement actuarial gains

'

'

'

'

'

'

'

'

'

'

'

'

Comprehensive income (loss)

($292)

'

'

'

($100)

'

'

'

'

($418)

($3,429)

($4,438)

GuarantorNonGuarantor_Unaudite4

Guarantor/Non-Guarantor Unaudited Condensed Consolidated Financial Information - Condensed Consolidating Statement of Cash Flows (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'	'	'
Net cash (used in) provided by operating activities	($19,903)	($6,317)	$10,783	$12,681	$5,721
Cash flows from investing activities:	'	'	'	'	'
Capital expenditures	-273	-603	-1,869	-2,731	-6,305
Net cash used in investing activities	-273	-603	-1,869	-2,731	-6,291
Cash flows from financing activities:	'	'	'	'	'
Payment of debt issue costs	-750	'	'	'	-710
Revolver borrowings	10,000	'	16,461	26,000	17,000
Revolver payments	-10,000	'	-16,461	-26,000	-17,000
Redeemable common stock purchased from ESOP Trust	-934	-1,975	-6,664	-4,843	-5,762
Redeemable common stock sold to ESOP Trust	934	1,129	2,166	1,302	5,158
Net cash used in financing activities	-750	-846	-10,528	-3,541	-5,307
Net (decrease) increase in cash and cash equivalents	-20,926	-7,766	-1,614	6,409	-5,877
Cash and cash equivalents at beginning of period	25,613	27,227	27,227	20,818	26,695
Cash and cash equivalents at end of period	4,687	19,461	25,613	27,227	20,818
Parent [Member]	'	'	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'	'	'
Net cash (used in) provided by operating activities	-19,934	-6,337	10,666	12,700	5,061
Cash flows from investing activities:	'	'	'	'	'
Capital expenditures	-263	-603	-1,792	-2,733	-5,694
Net cash used in investing activities	-263	-603	-1,792	-2,733	-5,680
Cash flows from financing activities:	'	'	'	'	'
Payment of debt issue costs	-750	'	'	'	-710
Revolver borrowings	10,000	'	16,461	26,000	17,000
Revolver payments	-10,000	'	-16,461	-26,000	-17,000
Redeemable common stock purchased from ESOP Trust	-934	-1,975	-6,664	-4,843	-5,762
Redeemable common stock sold to ESOP Trust	934	'	2,166	1,302	5,158
Net cash used in financing activities	-750	-846	-10,528	-3,541	-5,307
Net (decrease) increase in cash and cash equivalents	-20,947	-7,786	-1,654	6,426	-5,926
Cash and cash equivalents at beginning of period	25,617	27,271	27,271	20,844	26,770
Cash and cash equivalents at end of period	4,670	19,485	25,617	27,271	20,844
Guarantor Companies [Member]	'	'	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'	'	'
Net cash (used in) provided by operating activities	24	15	97	-19	636
Cash flows from investing activities:	'	'	'	'	'
Capital expenditures	-10	'	-77	2	-588
Net cash used in investing activities	-10	'	-77	2	-588
Cash flows from financing activities:	'	'	'	'	'
Net (decrease) increase in cash and cash equivalents	14	15	20	-17	48
Cash and cash equivalents at beginning of period	-24	-44	-44	-26	-74
Cash and cash equivalents at end of period	-10	-29	-24	-44	-26
Non-Guarantor Companies [Member]	'	'	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'	'	'
Net cash (used in) provided by operating activities	7	5	20	'	24
Cash flows from investing activities:	'	'	'	'	'
Capital expenditures	'	'	'	'	-23
Net cash used in investing activities	'	'	'	'	-23
Cash flows from financing activities:	'	'	'	'	'
Net (decrease) increase in cash and cash equivalents	7	5	20	'	1
Cash and cash equivalents at beginning of period	20	'	'	'	-1
Cash and cash equivalents at end of period	$27	$5	$20	'	'

Subsequent_Event_Additional_In

Subsequent Event - Additional Information (Detail) (Subsequent Event [Member])	1 Months Ended
	Jan. 31, 2014
Subsequent Event [Member]	'
Subsequent Event [Line Items]	'
Percentage of early tender cash payment	1.50%
Percentage of new warrants to purchase company's common stock	27.50%

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$25,613	$27,227
Accounts receivable, net	172,604	175,293
Receivable due from ESOP Trust	930	1,129
Prepaid expenses and other current assets	4,483	5,448
Total current assets	203,630	209,097
Property, plant and equipment, net	9,668	10,605
Intangible assets, net	2,040	5,242
Goodwill	398,921	398,921
Other assets	10,367	11,431
Total assets	624,626	635,296
Current liabilities:	'	'
Interest payable	17,758	17,658
Trade accounts payable	61,622	44,793
Accrued liabilities	39,393	52,460
Accrued payroll and related liabilities	37,954	39,926
Billings in excess of revenue earned	4,334	2,666
Total current liabilities	161,061	157,503
Secured Notes	322,286	306,502
Unsecured Notes	233,832	242,923
Accrued compensation and benefits, excluding current portion	5,736	5,905
Non-current portion of lease obligations	12,821	12,364
Deferred income taxes	58,130	51,156
Commitments and contingencies	'	'
Other liabilities	'	'
Redeemable common stock, $0.01 par value, 20,000,000 shares authorized; 7,641,493 shares issued and outstanding at December 31, 2013; 7,641,391 shares issued and outstanding at September 30, 2013	61,895	110,740
Common stock warrants	20,785	20,785
Accumulated other comprehensive loss	130	-149
Accumulated deficit	-252,050	-272,433
Total liabilities, redeemable common stock and stockholder's deficit	$624,626	$635,296

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Statement Of Financial Position [Abstract]	'	'	'
Redeemable common stock, par value	$0.01	$0.01	$0.01
Redeemable common stock, shares authorized	20,000,000	20,000,000	8,000,000
Redeemable common stock, shares issued	7,641,493	7,641,391	6,731,889
Redeemable common stock, shares outstanding	7,641,493	7,641,391	6,731,889

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (USD $)

3 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Income Statement [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

$185,380

'

'

'

$204,329

'

'

'

'

$848,972

$817,204

$787,314

Direct contract expense

145,275

'

'

'

160,635

'

'

'

'

669,504

632,831

603,481

Gross profit

40,105

42,822

46,633

46,319

43,694

47,673

46,472

46,681

43,547

179,468

184,373

183,833

Operating expenses

18,864

'

'

'

22,250

'

'

'

'

84,128

91,494

83,035

General and administrative

18,993

'

'

'

11,804

'

'

'

'

53,139

52,441

65,305

Operating income

2,248

'

'

'

9,640

'

'

'

'

42,201

40,438

35,493

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Interest income

11

'

'

'

17

'

'

'

'

55

78

45

Interest expense

-18,948

'

'

'

-18,919

'

'

'

'

-75,700

-74,934

-73,919

Other

-28

'

'

'

-15

'

'

'

'

-84

-55

32

Gains (losses) on extinguishment of debt

'

'

'

'

'

'

'

'

'

3,913

'

939

Total other (expense) income

-18,965

'

'

'

-18,917

'

'

'

'

-71,816

-74,911

-72,903

Loss before taxes

-16,717

'

'

'

-9,277

'

'

'

'

-29,615

-34,473

-37,410

Income tax expense

-1,745

'

'

'

-1,744

'

'

'

'

-6,977

-6,974

-6,974

Net loss

-18,462

-9,353

-7,087

-9,131

-11,021

-9,526

-8,866

-10,245

-12,810

-36,592

-41,447

-44,384

Basic and diluted loss per share

($2.41)

'

'

'

($1.64)

'

'

'

'

($5.39)

($6.74)

($7.83)

Basic and diluted weighted average common shares outstanding

7,659,817

'

'

'

6,726,417

'

'

'

'

6,787,660

6,148,438

5,671,977

Net loss

-18,462

-9,353

-7,087

-9,131

-11,021

-9,526

-8,866

-10,245

-12,810

-36,592

-41,447

-44,384

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Postretirement actuarial gains

'

'

'

'

'

'

'

'

'

279

26

55

Comprehensive loss

($18,462)

'

'

'

($11,021)

'

'

'

'

($36,313)

($41,421)

($44,329)

Consolidated_Statements_of_Red

Consolidated Statements of Redeemable Common Stock, and Stockholder's Deficit (USD $)	Total	Redeemable Common Stock [Member]	Common Stock Warrants [Member]	Comprehensive Loss [Member]	Accumulated Deficit [Member]
In Thousands, except Share data
Balances at Sep. 30, 2010	'	$150,792	$20,785	'	($246,270)
Balances, shares at Sep. 30, 2010	'	5,658,234	'	'	'
Redeemable common stock issued	'	14,059	'	'	'
Redeemable common stock issued, shares	'	597,240	'	'	'
Redeemable common stock retired	'	-5,762	'	'	'
Redeemable common stock retired, shares	'	-214,445	'	'	'
Change in common stock redemption value	'	-32,529	'	'	32,529
Postretirement medical plan actuarial benefit	'	'	'	55	'
Net loss	-44,384	'	'	-44,384	-44,384
Comprehensive loss	-44,329	'	'	-44,329	'
Balances at Sep. 30, 2011	'	126,560	20,785	'	-258,125
Balances, shares at Sep. 30, 2011	'	6,041,029	'	'	'
Redeemable common stock issued	'	16,162	'	'	'
Redeemable common stock issued, shares	'	938,492	'	'	'
Redeemable common stock retired	'	-4,843	'	'	'
Redeemable common stock retired, shares	'	-247,632	'	'	'
Change in common stock redemption value	'	-27,139	'	'	27,139
Postretirement medical plan actuarial benefit	'	'	'	26	'
Net loss	-41,447	'	'	-41,447	-41,447
Comprehensive loss	-41,421	'	'	-41,421	'
Balances at Sep. 30, 2012	'	110,740	20,785	'	-272,433
Balances, shares at Sep. 30, 2012	'	6,731,889	'	'	'
Redeemable common stock issued	'	14,794	'	'	'
Redeemable common stock issued, shares	'	1,316,594	'	'	'
Redeemable common stock retired	'	-6,664	'	'	'
Redeemable common stock retired, shares	'	-407,092	'	'	'
Change in common stock redemption value	'	-56,975	'	'	56,975
Postretirement medical plan actuarial benefit	'	'	'	279	'
Net loss	-36,592	'	'	-36,592	-36,592
Comprehensive loss	-36,313	'	'	-36,313	'
Balances at Sep. 30, 2013	'	$61,895	$20,785	'	($252,050)
Balances, shares at Sep. 30, 2013	'	7,641,391	'	'	'

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:	'	'	'
Net loss	($36,592)	($41,447)	($44,384)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'	'
Depreciation and amortization	7,363	11,741	11,409
Paid-in-kind interest	6,551	6,423	6,300
Bad debt expense	367	802	'
Amortization of debt issuance costs	10,571	10,421	10,143
Incentive and stock-based compensation	2,065	1,310	2,655
Gain on debt extinguishment	-3,913	'	-939
Deferred income taxes	6,974	6,974	6,974
Other gains and losses	-151	-95	29
Changes in assets and liabilities:	'	'	'
Accounts receivable	2,323	4,269	-6,332
Other assets	733	4,122	-1,277
Trade accounts payable	16,829	-7,562	7,869
Accrued liabilities	-4,122	16,513	12,370
Interest payable	100	266	175
Other liabilities	1,685	-1,056	729
Net cash used in operating activities	10,783	12,681	5,721
Cash flows from investing activities:	'	'	'
Capital expenditures	-1,869	-2,731	-6,305
Asset sales proceeds	'	'	14
Net cash used in investing activities	-1,869	-2,731	-6,291
Cash flows from financing activities:	'	'	'
Payment of debt issue costs	'	'	-710
Repurchase Unsecured Notes	-6,030	'	-3,993
Revolver borrowings	16,461	26,000	17,000
Revolver repayments	-16,461	-26,000	-17,000
Loan to ESOP Trust	-1,907	-477	-776
ESOP loan repayment	1,907	477	776
Redeemable common stock purchased from ESOP Trust	-6,664	-4,843	-5,762
Redeemable common stock sold to ESOP Trust	2,166	1,302	5,158
Net cash used in financing activities	-10,528	-3,541	-5,307
Net decrease in cash and cash equivalents	-1,614	6,409	-5,877
Cash and cash equivalents at beginning of period	27,227	20,818	26,695
Cash and cash equivalents at end of period	25,613	27,227	20,818
Supplemental disclosure of cash flow information:	'	'	'
Cash paid for interest	58,460	57,755	57,301
Cash paid (received) for taxes	'	'	'
Non-cash investing and financing activities:	'	'	'
Common stock issued to ESOP Trust in satisfaction of employer contribution liability	13,757	13,732	10,797
Landlord funded leasehold improvements	$493	$1,841	$2,823

Description_and_Formation_of_t2

Description and Formation of the Business	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Accounting Policies [Abstract]	'	'
Description and Formation of the Business	'	'
	(1) Description and Formation of the Business	(1) Description and Formation of the Business
	Alion Science and Technology Corporation and its subsidiaries (collectively, the Company, Alion or we) provide advanced engineering, information technology, naval architecture and operational solutions to strengthen national security and drive business results. For customers in defense, civilian government, foreign governments and commercial industries worldwide, Alion’s engineered solutions support smarter decision-making and enhanced readiness in rapidly-changing environments.	Alion Science and Technology Corporation and its subsidiaries (collectively, the Company, Alion or we) provide advanced engineering, information technology, naval architecture and operational solutions to strengthen national security and drive business results. For customers in defense, civilian government, foreign governments and commercial industries worldwide, Alion’s engineered solutions support smarter decision-making and enhanced readiness in rapidly-changing environments.
	Alion was formed as a for-profit S-Corporation in October 2001, to purchase substantially all of the assets and certain liabilities of IIT Research Institute (IITRI), a not-for-profit corporation controlled by the Illinois Institute of Technology (IIT). In December 2002, Alion acquired substantially all of IITRI’s assets and liabilities except its Life Sciences Operation, for $127.3 million. Prior to that, the Company’s activities were organizational in nature. In 2010, the Company became a C corporation when it ceased to qualify as an S corporation.	Alion was formed as a for-profit S-Corporation in October 2001, to purchase substantially all of the assets and certain liabilities of IIT Research Institute (IITRI), a not-for-profit corporation controlled by the Illinois Institute of Technology (IIT). In December 2002, Alion acquired substantially all of IITRI’s assets and liabilities except its Life Sciences Operation, for $127.3 million. Prior to that, the Company’s activities were organizational in nature. In 2010, the Company became a C corporation when it ceased to qualify as an S corporation.

Summary_of_Significant_Account3

Summary of Significant Accounting Policies	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Accounting Policies [Abstract]	'		'
Summary of Significant Accounting Policies	'		'
	-2	Summary of Significant Accounting Policies	(2) Summary of Significant Accounting Policies
	Basis of Presentation and Principles of Consolidation		Basis of Presentation and Principles of Consolidation
	The accompanying unaudited condensed consolidated financial statements include the accounts of Alion Science and Technology Corporation (a Delaware corporation), and its wholly-owned subsidiaries and have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission. Certain information and note disclosures normally included in the annual financial statements, prepared in accordance with generally accepted accounting principles in the United States of America (GAAP), have been omitted pursuant to those rules and regulations. However, the Company believes that the disclosures made are adequate to make the information presented not misleading. The statements are prepared on the accrual basis of accounting and include the accounts of Alion and its wholly-owned subsidiaries from their date of acquisition or formation. All inter-company accounts have been eliminated in consolidation. There have been no changes to Alion’s subsidiaries in the current fiscal year.		The accompanying audited consolidated financial statements include the accounts of Alion Science and Technology Corporation (a Delaware corporation) and its wholly-owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles on the accrual basis of accounting. The statements include the accounts of Alion and its wholly-owned subsidiaries from date of formation or acquisition. All inter-company accounts have been eliminated in consolidation. The wholly-owned subsidiaries are:
	In management’s opinion, the accompanying unaudited condensed consolidated financial statements reflect all adjustments consisting of normal recurring adjustments and reclassifications that are necessary for fair presentation of the periods presented. The results for the three months ended December 31, 2013 are not necessarily indicative of the results to be expected for the full fiscal year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s latest annual report on Form 10-K for the year ended September 30, 2013.
	Going Concern Assumption			•	Innovative Technology Solutions Corporation (ITSC) – acquired October 2003
	The accompanying financial statements are prepared on the going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Alion has a history of losses that has resulted, in part, in the Company not having the means to repay the principal associated with our Secured and Unsecured Notes as they come due on November 1, 2014 and February 1, 2015, respectively. In the first quarter of fiscal 2014, our Secured Notes were reclassified to current liabilities based on their November 1, 2014 maturity. Our Unsecured Notes will be reclassified to current liabilities in the second quarter of fiscal 2014.
	Our liabilities exceed our assets which makes refinancing our debt more difficult and expensive. Operating cash flow is insufficient to repay the Secured and Unsecured Notes at maturity, which raises substantial doubt as to the Company’s ability to continue as a going concern.			•	Alion - IPS Corporation (IPS) – acquired February 2004
	Management’s current forecasts of future results could differ materially due to general economic uncertainties, sequestration’s effect on government spending levels in the coming fiscal year, collections delays from the October 2013 government shutdown and risks associated with future federal government procurement and contracting actions. Management’s cash flow projections indicate that absent a refinancing transaction or series of transactions, the Company will be unable to pay the principal and accumulated unpaid interest on its Secured and Unsecured Notes when those instruments come due in November 2014 and February 2015.
	Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of receiving an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this financial covenant. The Company paid no fee for this waiver.			•	Alion - METI Corporation (METI) – acquired February 2005
	Alion depends heavily on federal government prime contracts and subcontracts which account for nearly all the Company’s revenue. Interruptions in the government funding process, whether from federal budget delays, debt ceiling limitations, government shutdowns, sequestration or Department of Defense spending cuts could materially adversely affect the Company’s revenue and cash flows for the coming fiscal year and beyond. This could cause Alion to be unable to fund operations, meet debt service requirements or comply with the Credit Agreement’s Consolidated EBITDA covenant.			•	Alion - CATI Corporation (CATI) – acquired February 2005
	If Alion were unable to meet the Credit Agreement Consolidated EBITDA covenant, the Company would be unable to borrow funds under the revolving credit facility which would remove a source of liquidity for the Company. Alion could be required to immediately repay any amount then outstanding under the Credit Agreement. The Company could seek an additional covenant waiver or an amendment to the Credit Agreement in order to preserve its ability to borrow funds as and when needed. The Credit Agreement expires on August 22, 2014. Management can provide no assurance that Alion would be able to obtain an amendment or waiver, or if one were available, that the terms would be favorable. If the Company were unable to obtain a requested waiver or amendment, it might be unable to pay its debts as they became due. In each of the past three fiscal years, Alion generated sufficient cash flow from operations to fulfill its financial commitments, including debt service.
	Management is actively engaged in efforts to refinance, retire or amend Alion’s existing debt agreements. On December 24, 2013, we executed a Refinancing Support Agreement with the holders of a majority of our outstanding Unsecured Notes regarding potential transactions to refinance our outstanding indebtedness. Management can provide no assurance that Alion will be able to conclude a refinancing of its Unsecured Notes or that additional financing will be available to retire or replace the Secured Notes, and if available, that terms of any transaction would be favorable.			•	Alion International Corporation (Alion International) – established February 2005
	On the basis of these risks and uncertainties, management has determined that there is substantial doubt about the Company’s ability to continue as a going concern. Alion’s unaudited condensed consolidated financial statements do not include any adjustments to reflect the possible effects on the recoverability of assets or the amounts of liabilities that may result from resolving uncertainties about the Company’s ability to continue as a going concern.
	Fiscal, Quarter and Interim Periods			•	Alion Science and Technology (Canada) Corporation – established February 2005
	Alion’s fiscal year ends on September 30. The Company operates based on a three-month quarter, four-quarter fiscal year with quarters ending December 31, March 31, June 30, and September 30.
	Use of Estimates			•	Alion - JJMA Corporation (JJMA) – acquired April 2005
	Preparing financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect amounts reported for assets and liabilities, disclosures of contingent assets and liabilities as of financial statement dates and amounts reported for operating results for each period presented. Actual results are likely to differ from those estimates, but management does not believe such differences will materially affect Alion’s financial position, results of operations, or cash flows.
	Revenue Recognition			•	Alion - BMH Corporation (BMH) – acquired February 2006
	Alion derives its revenue from delivering technology services under three types of contracts. Some contracts provide for reimbursement of costs plus fees; others are fixed-price or time-and-material type contracts. We recognize revenue when a contract has been executed, the contract price is fixed or determinable, delivery of services or products has occurred, and our ability to collect the contract price is considered reasonably assured. Alion applies the percentage-of-completion method in Accounting Standards Codification (ASC) 605 – Revenue Recognition to recognize revenue.
	Alion recognizes revenue on cost-reimbursement contracts as it incurs costs and includes estimated fees earned. The Company recognizes time-and-material contract revenue at negotiated, fixed, contractually billable rates as it delivers labor hours and incurs other direct expenses. We use various performance measures under the percentage-of-completion method to recognize revenue for fixed-price contracts. Estimating contract costs at completion and recognizing revenue appropriately involve significant management estimates. Actual costs may differ from estimated costs and affect estimated profitability and revenue recognition timing. From time to time, facts develop that require us to revise estimated total costs or expected revenue. We record the cumulative effect of revised estimates in the period when the facts requiring revised estimates become known. We recognize the full amount of anticipated losses on any contract in the period a loss becomes known. For each of the periods presented, the cumulative effects of revised estimates were immaterial to the Company’s financial performance.			•	Washington Consulting, Inc. (WCI) – acquired February 2006
	U.S. federal government contracts are subject to periodic funding by our contracting agency customers. A customer may fund a contract at inception or incrementally throughout the period of performance as services are provided. If we determine contract funding is not probable, we defer revenue recognition until realization is probable. The federal government can audit Alion’s contract costs and adjust amounts through negotiation. The federal government considers Alion a major contractor and maintains an office on site. The Defense Contract Audit Agency (DCAA) is currently auditing our 2007 claimed indirect costs. We are negotiating our 2006 indirect rates and have settled our rates through 2005. We timely submitted our indirect cost proposals for all open fiscal years. We have recorded revenue on federal government contracts in amounts we expect to realize.
	We recognize revenue on unpriced change orders as we incur expenses and only to the extent it is probable we will recover such costs. The Company recognizes revenue in excess of costs on unpriced change orders only when management can also estimate beyond a reasonable doubt the amount of excess and experience provides a sufficient basis for recognition. Alion recognizes revenue on claims as expenses are incurred and only to the extent it is probable we will recover such costs and can reliably estimate the amount we will recover.			•	Alion—MA&D Corporation (MA&D) – acquired May 2006
	Income Taxes
	Alion accounts for income taxes by applying the provisions in currently enacted tax laws. We determine deferred income taxes based on the estimated future tax effects of differences between the financial statement and tax bases of our assets and liabilities. Deferred income tax provisions and benefits change as assets or liabilities change from year to year. In providing for deferred taxes, Alion considers the tax regulations of the jurisdictions where we operate; estimated future taxable income; and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies change, the carrying value of deferred tax assets and liabilities may require adjustment.			•	Alion Offshore Services, Inc. (Alion Offshore) – established May 2006
	Alion has a history of operating losses for both tax and financial statement purposes. The Company has recorded valuation allowances equal to deferred tax assets based on the likelihood that we may not be able to realize the value of these assets. Alion recognizes the benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain our position following an audit. For tax positions meeting the “more likely than not” threshold, we recognize the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
	Cash and Cash Equivalents			•	Washington Consulting Government Services, Inc. (WCGS) – established July 2007
	The Company considers cash in banks, and deposits with financial institutions with maturities of three months or less at time of purchase which it can liquidate without prior notice or penalty, to be cash and cash equivalents.
	Accounts Receivable and Billings in Excess of Revenue Earned			•	Alion Asia Corporation (Alion Asia) – established May 2012
	Accounts receivable include billed accounts receivable and unbilled receivables. Unbilled receivables consist of costs and fees which are billable upon occurrence of a specific event, amounts billable after the balance sheet date and revenue in excess of billings on uncompleted contracts (accumulated project expenses and fees which were not billed or were not currently billable as of the date of the consolidated balance sheet). Unbilled accounts receivable include revenue recognized for customer-requested work Alion performed on new and existing contracts for which the Company had not received contracts or contract modifications. Accounts receivable are stated as estimated realized value. The allowance for doubtful accounts is Alion’s best estimate of the amount of probable losses in the Company’s existing billed and unbilled accounts receivable. The Company determines the allowance using specific identification and historical write-off experience based on receivable age. Billings in excess of revenue and advance collections from customers represent amounts received from or billed to customers in excess of project revenue recognized to date.
	Property, Plant and Equipment			•	Alion Maritime India Private Limited (Alion India) – established May 2013
	Leasehold improvements, software and equipment are recorded at cost. Maintenance and repairs that do not add significant value or significantly lengthen an asset’s useful life are charged to current operations. Software and equipment are depreciated on the straight-line method over their estimated useful lives (typically 3 years for software and 5 years for equipment). Leasehold improvements are amortized on the straight-line method over the shorter of the asset’s estimated useful life or the life of the lease. Upon sale or retirement of an asset, costs and related accumulated depreciation are deducted from the accounts, and any gain or loss is recognized in the unaudited condensed consolidated statements of operations.		Fiscal, Quarter and Interim Periods
	Goodwill		Alion’s fiscal year ends on September 30. The Company operates based on a three-month quarter, four-quarter fiscal year with quarters ending December 31, March 31, June 30, and September 30.
	Alion assigns the purchase price paid to acquire the stock or assets of a business to the net assets acquired based on the estimated fair value of assets acquired and liabilities assumed. Goodwill is the purchase price in excess of the estimated fair value of the tangible net assets and separately identified intangible assets acquired. There have been no changes to goodwill carrying value this year.		Use of Estimates
	The Company accounts for goodwill and other intangible assets in accordance with the provisions of ASC 350 – Intangibles-Goodwill and Other. Alion operates in one segment and tests goodwill at the reporting unit level. There are two reporting units. We review goodwill for impairment in the fourth quarter each year, and whenever events or circumstances indicate goodwill might be impaired. We are required to recognize an impairment loss to the extent our goodwill carrying value at the reporting unit level exceeds fair value. Evaluating goodwill involves significant management estimates. To date, our annual reviews have resulted in no goodwill impairment adjustments. See Note 8 for a detailed discussion of the Company’s goodwill impairment testing process.		Preparing financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect amounts reported for assets and liabilities, disclosures of contingent assets and liabilities as of financial statement dates and amounts reported for operating results for each period presented. Actual results are likely to differ from those estimates, but management does not believe such differences will materially affect Alion’s financial position, results of operations, or cash flows.
	Intangible Assets
	Alion amortizes intangible assets as it consumes economic benefits over estimated useful lives. As of December 31, 2013, the Company had approximately $1.7 million in net intangible assets, including contracts purchased in the JJMA acquisition and purchased software licenses. The JJMA contract portfolio has a remaining useful life of approximately 1.5 years.		Summary of Critical Accounting Policies
	Redeemable Common Stock		Going Concern Assumption
	There is no public market for Alion’s redeemable common stock and therefore no observable price for its equity, individually or in the aggregate. The Employee Stock Ownership Plan (ESOP) Trust holds all the Company’s outstanding common stock. Under certain circumstances, ESOP beneficiaries can require the ESOP Trust to distribute the value of their beneficial interests. The Internal Revenue Code (IRC) and the Employee Retirement Income Security Act (ERISA) require the Company to offer ESOP participants who receive Alion common stock a liquidity put right. The put right requires the Company to purchase distributed shares at their then- current fair market value at any time during two put option periods. Common stock distributed by the ESOP Trust is subject to a right of first refusal. Prior to any subsequent transfer, shares must first be offered to the Company and then to the ESOP Trust. Eventual redemption of shares of Alion common stock as a result of distributions is outside the Company’s control. Therefore, Alion classifies its outstanding shares of redeemable common stock as other than permanent equity.		The accompanying financial statements are prepared on the going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Alion has a history of losses that has resulted, in part, in the Company not having the means to repay the principal associated with our Secured and Unsecured Notes as they come due on November 1, 2014 and February 1, 2015, respectively. Further, liabilities in excess of our assets makes refinancing our debt more difficult and expensive, and an insufficient level of cash flow from operating activities to repay the Secured and Unsecured Notes at maturity, raises substantial doubt as to the Company’s ability to continue as a going concern.
	At each reporting date, Alion is required to increase or decrease the reported value of its outstanding common stock to reflect its estimated redemption value. Management estimates the value of Alion’s obligation to repurchase its outstanding shares of redeemable common stock by considering, in part, the most recent price at which the Company was able to sell shares to the ESOP Trust. The reported value of outstanding redeemable common stock equals the current share price multiplied by total shares issued and outstanding.		Management’s current forecasts of future results could differ materially due to general economic uncertainties, sequestration’s effect on government spending levels in the coming fiscal year, collections delays from the October 2013 government shutdown and risks associated with future federal government procurement and contracting actions. Management’s cash flow projections indicate that absent a refinancing transaction or series of transactions, the Company will be unable to pay the principal and accumulated unpaid interest on its Secured and Unsecured Notes when those instruments come due in November 2014 and February 2015.
	In its fiduciary capacity, the ESOP Trustee is independent of the Company and its management. Consistent with its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the ESOP Trustee may acquire or dispose of investments in Alion common stock. The Audit and Finance Committee of Alion’s Board of Directors reviews the reasonableness of the amount management has determined Alion should recognize for the Company’s obligation to repurchase shares of its outstanding redeemable common stock. The Audit and Finance Committee considers various factors in its review, including, in part, the most recent valuation report prepared for, and the share price selected by the ESOP Trustee.		Alion depends heavily on federal government prime contracts and subcontracts which account for nearly all the Company’s revenue. Interruptions in the government funding process, whether from federal budget delays, debt ceiling limitations, government shutdowns, sequestration or Department of Defense spending cuts could materially adversely affect the Company’s revenue and cash flows for the coming fiscal year and beyond. This could cause Alion to be unable to fund operations, meet debt service requirements or comply with the Credit Agreement’s Consolidated EBITDA covenant.
	Alion records changes in the reported value of its outstanding common stock through an offsetting charge or credit to accumulated deficit. The Company recognizes changes in the fair value of its redeemable common stock on March 31 and September 30 each year. The accumulated deficit at December 31, 2013, included a $67.5 million cumulative benefit for changes in share price which reduced the Company’s aggregate share redemption obligation. Outstanding redeemable common stock had an aggregate fair value of approximately $61.9 million as of December 31, 2013.		Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of receiving an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this financial covenant. The Company paid no fee for this waiver
			If Alion were unable to meet the Credit Agreement Consolidated EBITDA covenant, the Company would be unable to borrow funds under the revolving credit facility which would remove a source of liquidity for the Company. Alion could be required to immediately repay any amount then outstanding under the Credit Agreement. The Company could seek an additional covenant waiver or an amendment to the Credit Agreement in order to preserve its ability to borrow funds as and when needed. The Credit Agreement expires on August 22, 2014. Management can provide no assurance that Alion would be able to obtain an amendment or waiver, or if one were available, that the terms would be favorable. If the Company were unable to obtain a requested waiver or amendment, it might be unable to pay its debts as they became due. In each of the past three fiscal years, Alion generated sufficient cash flow from operations to fulfill its financial commitments, including debt service.
	Concentration of Credit Risk		Management is actively engaged in identifying additional potential sources of cash to refinance, retire or amend Alion’s existing debt agreements. We have reached a preliminary understanding with the holders of a majority of our outstanding Unsecured Notes regarding potential refinancing transactions involving our outstanding indebtedness and are negotiating a definitive agreement. However, Management can provide no assurance that Alion will be able to conclude a refinancing of its Unsecured Notes or that additional financing will be available to retire or replace its Secured Notes, and if available, that terms of any transaction would be favorable.
	Alion is subject to credit risk for its cash equivalents and accounts receivable. The Company believes the high credit quality of its cash equivalent investments limits its credit risk with respect to such investments. Alion believes its concentration of credit risk with respect to accounts receivable is limited as the receivables are principally due from the federal government. Approximately 21% of the Company’s receivables are due from commercial customers including other prime contractors.		On the basis of these risks and uncertainties, management has determined that there is substantial doubt about the Company’s ability to continue as a going concern. Alion’s audited consolidated financial statements do not include any adjustments to reflect the possible effects on the recoverability of assets or the amounts of liabilities that may result from resolving uncertainties about the Company’s ability to continue as a going concern.
	Fair Value of Financial Instruments		Revenue Recognition
	Alion is required to disclose the fair value of its financial instruments but is not required to record its senior long-term debt at fair value. See Note 10 for a discussion of Alion’s current and long-term debt and Note 11 for the related fair value disclosures. The fair value of cash, cash equivalents, accounts payable and accounts receivable does not differ materially from carrying value because of the short maturity of those instruments.		Alion derives its revenue from delivering technology services under three types of contracts. Some contracts provide for reimbursement of costs plus fees; others are fixed-price or time-and-material type contracts. We recognize revenue when a contract has been executed, the contract price is fixed or determinable, delivery of services or products has occurred, and our ability to collect the contract price is considered reasonably assured. Alion applies the percentage-of-completion method in Accounting Standards Codification (ASC) 605 – Revenue Recognition to recognize revenue.
	Off-Balance Sheet Financing Arrangements
	Alion accounts for operating leases entered into in the routine course of business in accordance with ASC 840 – Leases. We have no off-balance sheet financing arrangements other than operating leases and letters of credit under our revolving credit facility. Alion has no relationship with any unconsolidated or special purpose entity and has not issued any associated guarantees.		Alion recognizes revenue on cost-reimbursement contracts as it incurs costs and includes estimated fees earned. The Company recognizes time-and-material contract revenue at negotiated, fixed, contractually billable rates as it delivers labor hours and incurs other direct expenses. We use various performance measures under the percentage-of-completion method to recognize revenue for fixed-price contracts. Estimating contract costs at completion and recognizing revenue appropriately involve significant management estimates. Actual costs may differ from estimated costs and affect estimated profitability and revenue recognition timing. From time to time, facts develop that require us to revise estimated total costs or expected revenue. We record the cumulative effect of revised estimates in the period when the facts requiring revised estimates become known. We recognize the full amount of anticipated losses on any contract in the period a loss becomes known. For each of the periods presented, the cumulative effects of revised estimates were immaterial to the Company’s financial performance.
			U.S. federal government contracts are subject to periodic funding by our contracting agency customers. A customer may fund a contract at inception or incrementally throughout the period of performance as services are provided. If we determine contract funding is not probable, we defer revenue recognition until realization is probable. The federal government can audit Alion’s contract costs and adjust amounts through negotiation. The federal government considers Alion a major contractor and maintains an office on site. The Defense Contract Audit Agency (DCAA) is currently auditing our 2007 claimed indirect costs. We are negotiating our 2006 indirect rates and have settled our rates through 2005. We timely submitted our indirect cost proposals for all open fiscal years. We have recorded revenue on federal government contracts in amounts we expect to realize.
			We recognize revenue on unpriced change orders as we incur expenses and only to the extent it is probable we will recover such costs. The Company recognizes revenue in excess of costs on unpriced change orders only when management can also estimate beyond a reasonable doubt the amount of excess and experience provides a sufficient basis for recognition. Alion recognizes revenue on claims as expenses are incurred and only to the extent it is probable we will recover such costs and can reliably estimate the amount we will recover.
			Income Taxes
			Alion accounts for income taxes by applying the provisions in currently enacted tax laws. We determine deferred income taxes based on the estimated future tax effects of differences between the financial statement and tax bases of our assets and liabilities. Deferred income tax provisions and benefits change as assets or liabilities change from year to year. In providing for deferred taxes, Alion considers the tax regulations of the jurisdictions where we operate; estimated future taxable income; and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies change, the carrying value of deferred tax assets and liabilities may require adjustment.
			Alion has a history of operating losses for both tax and financial statement purposes. The Company has recorded valuation allowances equal to deferred tax assets based on the likelihood that we may not be able to realize the value of these assets. Alion recognizes the benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain our position following an audit. For tax positions meeting the “more likely than not” threshold, we recognize the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
			Cash and Cash Equivalents
			The Company considers cash in banks, and deposits with financial institutions with maturities of three months or less at time of purchase which it can liquidate without prior notice or penalty, to be cash and cash equivalents.
			Accounts Receivable and Billings in Excess of Revenue Earned
			Accounts receivable include billed accounts receivable and unbilled receivables. Unbilled receivables consist of costs and fees which are billable upon occurrence of a specific event, amounts billable after the balance sheet date and revenue in excess of billings on uncompleted contracts (accumulated project expenses and fees which were not billed or were not currently billable as of the date of the consolidated balance sheet). Unbilled accounts receivable include revenue recognized for customer-requested work Alion performed on new and existing contracts for which the Company had not received contracts or contract modifications. Accounts receivable are stated as estimated realized value. The allowance for doubtful accounts is Alion’s best estimate of the amount of probable losses in the Company’s existing billed and unbilled accounts receivable. The Company determines the allowance using specific identification and historical write-off experience based on receivable age. Billings in excess of revenue and advance collections from customers represent amounts received from or billed to customers in excess of project revenue recognized to date.
			Property, Plant and Equipment
			Leasehold improvements, software and equipment are recorded at cost. Maintenance and repairs that do not add significant value or significantly lengthen an asset’s useful life are charged to current operations. Software and equipment are depreciated on the straight-line method over their estimated useful lives (typically 3 years for software and 5 years for equipment). Leasehold improvements are amortized on the straight-line method over the shorter of the asset’s estimated useful life or the life of the lease. Upon sale or retirement of an asset, costs and related accumulated depreciation are deducted from the accounts, and any gain or loss is recognized in the audited consolidated statements of operations.
			Goodwill
			Alion assigns the purchase price paid to acquire the stock or assets of a business to the net assets acquired based on the estimated fair value of assets acquired and liabilities assumed. Goodwill is the purchase price in excess of the estimated fair value of the tangible net assets and separately identified intangible assets acquired. There have been no changes to goodwill carrying value this year.
			The Company accounts for goodwill and other intangible assets in accordance with the provisions of ASC 350 – Intangibles-Goodwill and Other. Alion operates in one segment and tests goodwill at the reporting unit level. There are two reporting units. We review goodwill for impairment in the fourth quarter each year, and whenever events or circumstances indicate goodwill might be impaired. We are required to recognize an impairment loss to the extent our goodwill carrying value at the reporting unit level exceeds fair value. Evaluating goodwill involves significant management estimates. To date, our annual reviews have resulted in no goodwill impairment adjustments. See Note 9 for a detailed discussion of the Company’s goodwill impairment testing process.
			Intangible Assets
		Alion amortizes intangible assets as it consumes economic benefits over estimated useful lives. As of September 30, 2013, the Company had approximately $2.0 million in net intangible assets, including contracts purchased in the JJMA acquisition and purchased software licenses. The JJMA contract portfolio has a remaining useful life of approximately 1.6 years.
		Redeemable Common Stock
		There is no public market for Alion’s redeemable common stock and therefore no observable price for its equity, individually or in the aggregate. The Employee Stock Ownership Plan (ESOP) Trust holds all the Company’s outstanding common stock. Under certain circumstances, ESOP beneficiaries can require the ESOP Trust to distribute the value of their beneficial interests. The Internal Revenue Code (IRC) and the Employee Retirement Income Security Act (ERISA) require the Company to offer ESOP participants who receive Alion common stock a liquidity put right. The put right requires the Company to purchase distributed shares at their then-current fair market value at any time during two put option periods. Common stock distributed by the ESOP Trust is subject to a right of first refusal. Prior to any subsequent transfer, shares must first be offered to the Company and then to the ESOP Trust. Eventual redemption of shares of Alion common stock as a result of distributions is outside the Company’s control. Therefore, Alion classifies its outstanding shares of redeemable common stock as other than permanent equity.
		At each reporting date, Alion is required to increase or decrease the reported value of its outstanding common stock to reflect its estimated redemption value. Management estimates the value of Alion’s obligation to repurchase its outstanding shares of redeemable common stock by considering, in part, the most recent price at which the Company was able to sell shares to the ESOP Trust. The reported value of outstanding redeemable common stock equals the current share price multiplied by total shares issued and outstanding.
		In its fiduciary capacity, the ESOP Trustee is independent of the Company and its management. Consistent with its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the ESOP Trustee may acquire or dispose of investments in Alion common stock. The Audit and Finance Committee of Alion’s Board of Directors reviews the reasonableness of the amount management has determined Alion should recognize for the Company’s obligation to repurchase shares of its outstanding redeemable common stock. The Audit and Finance Committee considers various factors in its review, including, in part, the most recent valuation report prepared for, and the share price selected by the ESOP Trustee.
		Alion records changes in the reported value of its outstanding common stock through an offsetting charge or credit to accumulated deficit. The Company recognizes changes in the fair value of its redeemable common stock on March 31 and September 30 each year. The accumulated deficit at September 30, 2013, included a $67.5 million cumulative benefit for changes in share price which reduced the Company’s aggregate share redemption obligation. Outstanding redeemable common stock had an aggregate fair value of approximately $61.9 million as of September 30, 2013.
		Concentration of Credit Risk
		Alion is subject to credit risk for its cash equivalents and accounts receivable. The Company believes the high credit quality of its cash equivalent investments limits its credit risk with respect to such investments. Alion believes its concentration of credit risk with respect to accounts receivable is limited as the receivables are principally due from the federal government. Approximately 22% of the Company’s receivables are due from commercial customers including other prime contractors.
		Fair Value of Financial Instruments
		Alion is required to disclose the fair value of its financial instruments, but is not required to record its senior long term debt at fair value. See Note 11 for a discussion of Alion’s long term debt and Note 12 for the related fair value disclosures. The fair value of cash, cash equivalents, accounts payable and accounts receivable is not materially different from carrying value because of the short maturity of those instruments.
		Off-Balance Sheet Financing Arrangements
		Alion accounts for operating leases entered into in the routine course of business in accordance with ASC 840 Leases. We have no off-balance sheet financing arrangements other than operating leases and letters of credit under our revolving credit facility. Alion has no relationship with any unconsolidated or special purpose entity and has not issued any guarantees.
		Recently Issued Accounting Pronouncements
		In July 2013, FASB issued Accounting Standards Update 2013-11 (ASU 2013-11)—Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. ASU 2013-11 updates Accounting Standards Codification Topic 740 – Income Taxes and is intended to eliminate diversity in accounting practice. In general, ASU 2013-11 requires an entity to reduce deferred tax assets for unrecognized tax benefits related to net operating loss or tax credit carryforwards. An entity is to present unrecognized tax benefits as a liability when: (1) the related net operating loss or tax credit carryforward is unavailable to settle the liability; or (2) tax law permits and the entity intends not to use its deferred tax assets to offset taxes arising from disallowing the entity’s tax position. ASU 2013-11 affects presentation of amounts and does not affect income tax expense. Management does not believe that adopting ASU 2013-11 will affect the Company’s operating results, financial position or cash flows.
		In January 2013, the FASB issued Accounting Standards Update 2013-01 (ASU 2013-01) Balance Sheet Topic (Topic 210)—Clarifying the Scope and Disclosures About Offsetting Assets and Liabilities. ASU 2013-01 is effective for fiscal years beginning after January 1, 2013 and provides guidance on what disclosures to make about offsetting balances. Alion currently does not offset any significant balances and has no related disclosure. The Company does not believe adopting ASU 2013-01 will affect Alion’s consolidated financial position or operating results.

Business_Dispositions

Business Dispositions	12 Months Ended
	Sep. 30, 2013
Text Block [Abstract]	'
Business Dispositions	'
	(3) Business Dispositions
	Dispositions
	On July 9, 2010, Alion’s WCGS subsidiary sold several U.S. Navy contracts and certain related assets and liabilities for $5.0 million and recognized a $5.1 million gain on the sale. WCGS continued to provide professional engineering services to the U.S. Navy under several existing contracts through September 30, 2011. Alion provides professional engineering services to the U.S. Navy under a variety of existing contracts.
	On September 30, 2010, Alion sold its former HFA subsidiary for $275 thousand. The Company recognized a $2.4 million loss on the sale.
	Neither the WCGS contract sale, nor Alion’s sale of its HFA subsidiary was material or significant; therefore no pro forma disclosures are presented in these consolidated financial statements.

Employee_Stock_Ownership_Plan_2

Employee Stock Ownership Plan (ESOP) and ESOP Trust	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Text Block [Abstract]	'		'
Employee Stock Ownership Plan (ESOP) and ESOP Trust	'		'
	-3	Employee Stock Ownership Plan (ESOP) and ESOP Trust	(4) Employee Stock Ownership Plan (ESOP) and ESOP Trust
	In December 2001, the Company adopted the Alion Science and Technology Corporation Employee Ownership, Savings and Investment Plan (the Plan, the KSOP) and established the ESOP Trust. The Plan, a tax qualified retirement plan, includes an ESOP and a 401(k) component. In April 2010, the Internal Revenue Service (IRS) issued a determination letter that the ESOP Trust and the Plan, as amended and restated as of October 1, 2006, including Plan amendments executed in June 2009 and May 2010 qualify under IRC Sections 401(a) and 501(a).		In December 2001, the Company adopted the Alion Science and Technology Corporation Employee Ownership, Savings and Investment Plan (the Plan, the KSOP) and established the ESOP Trust. The Plan, a tax qualified retirement plan, includes an ESOP and a 401(k) component. In April 2010, the Internal Revenue Service (IRS) issued a determination letter that the ESOP Trust and the Plan, as amended and restated as of October 1, 2006, including Plan amendments executed in June 2009 and May 2010 qualify under IRC Sections 401(a) and 501(a).
	In August 2008, Alion amended the Trust Agreement between the Company and the ESOP Trust. In June 2011, the Company amended the Plan to eliminate the one year service requirement for employer 401(k) matching contributions; to automatically enroll new hires in the Plan’s 401(k) component; and to designate profit sharing contributions exclusively in Alion common stock.		In August 2008, Alion amended the Trust Agreement between the Company and the ESOP Trust. In June 2011, the Company amended the Plan to eliminate the one year service requirement for employer 401(k) matching contributions; to automatically enroll new hires in the Plan’s 401(k) component; and to designate profit sharing contributions exclusively in Alion common stock.
	In September 2013, Alion amended the Plan to delay transfer to the Company of employee contributions for investment in the ESOP component of the Plan and to delay the Company’s contribution to the Plan for the six months ended September 30, 2013. The September 2013 amendment permitted delaying the valuation of Alion’s common stock until the due date (including extensions) for filing the Company’s federal tax return for the current fiscal year. The Company believes the Plan and the ESOP Trust have been designed and are being operated in compliance with applicable IRC requirements.		In September 2013, Alion amended the Plan to delay transfer to the Company of employee contributions for investment in the ESOP component of the Plan and to delay the Company’s contribution to the Plan for the six months ended September 30, 2013. The September 2013 amendment also delayed the valuation of Alion’s common stock until the due date (including extensions) for filing the Company’s federal tax return for the current fiscal year. The Company believes the Plan and the ESOP Trust have been designed and are being operated in compliance with applicable IRC requirements.

Loss_Per_Share1

Loss Per Share	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Earnings Per Share [Abstract]	'		'
Loss Per Share	'		'
	-4	Loss Per Share	(5) Loss Per Share
	Basic and diluted loss per share is computed by dividing net loss by the weighted average number of common shares outstanding excluding the impact of warrants. Warrants are anti-dilutive for all periods presented even after including required adjustments to the earnings per share numerator. On March 22, 2010, Alion issued 310,000 Units that included the Secured Notes and warrants to purchase 602,614 shares of Alion common stock The Secured Note warrants have a penny per share exercise price, are currently exercisable and expire March 15, 2017. The Secured Note warrants are not redeemable or puttable; they are classified as permanent equity.		Basic and diluted loss per share is computed by dividing net loss by the weighted average number of common shares outstanding excluding the impact of warrants. The warrants are anti-dilutive for all periods presented even after including required adjustments to the earnings per share numerator. On March 22, 2010, Alion issued 310,000 Units that included the Secured Notes and warrants to purchase 602,614 shares of Alion common stock The Secured Note warrants have a penny per share exercise price, are currently exercisable and expire March 15, 2017. The Secured Note warrants are not redeemable or puttable; they are classified as permanent equity.

Redeemable_Common_Stock1

Redeemable Common Stock	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Text Block [Abstract]	'		'
Redeemable Common Stock	'		'
	-5	Redeemable Common Stock
	The ESOP Trust owns all of Alion’s issued and outstanding common stock, for the benefit of current and former employee participants in the Alion KSOP. Participants and beneficiaries are entitled to a distribution of the fair value of their vested ESOP account balance upon death, disability, retirement or termination of employment. The Plan permits distributions to be paid over a five year period commencing the first ESOP valuation after a participant’s retirement at age 65, death or disability. Alion can delay distributions to other terminating participants for six years before commencing payment over a subsequent five year period. The Company intends to pay distribution requests in annual installments and defer initial payments as permitted.		(6) Redeemable Common Stock
	Terminating ESOP participants can hold or immediately sell their distributed shares to the Company. If a participant elects to hold distributed shares, the IRC and ERISA require Alion to offer a put option to allow the recipient to sell stock to Alion at the estimated fair value share price based on the most recent price at which the Company was able to sell shares to the ESOP Trust ($16.25 at March 31, 2013 and $8.10 at September 30, 2013). The put right requires Alion to purchase distributed shares during two put option periods at then-current fair market value.		The ESOP Trust owns all of Alion's issued and outstanding common stock, for the benefit of current and former employee participants in the Alion KSOP. Participants and beneficiaries are entitled to a distribution of the fair value of their vested ESOP account balance upon death, disability, retirement or termination of employment. The Plan permits distributions to be paid over a five year period commencing the year after a participant's retirement at age 65, death or disability. Alion can delay distributions to other terminating participants for six years before commencing payment over a subsequent five year period. The Company intends to pay distribution requests in annual installments and defer initial payments as permitted.
	Consistent with its duty of independence from Alion management and its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the Trustee may acquire or dispose of investments in Alion common stock. The September 30, 2013 valuation occurred on its normal schedule.
	Alion management determines, and the Board of Directors’ Audit and Finance Committee reviews, the reasonableness of Alion’s recorded redeemable common stock liability. The Audit and Finance Committee considers various factors in its review, including in part, the ESOP valuation report and the share price selected by the ESOP Trustee. Management considers the share price selected by the ESOP Trustee along with other factors in estimating Alion’s aggregate liability for outstanding redeemable common stock.		Terminating ESOP participants can hold or immediately sell their distributed shares to the Company. If a participant elects to hold distributed shares, the IRC and ERISA require Alion to offer a put option to allow the recipient to sell stock to Alion at the estimated fair value share price based on the most recent price at which the Company was able to sell shares to the ESOP Trust ($16.25 at March 31, 2013 and $8.10 at September 30, 2013). The put right requires Alion to purchase distributed shares during two put option periods at then-current fair market value.
			Consistent with its duty of independence from Alion management and its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the Trustee may acquire or dispose of investments in Alion common stock. In September 2013, Alion amended the Plan to delay the semi-annual September 30th valuation of Alion's common stock until the due date (including extensions) for filing the Company's federal tax return for the current fiscal year. The semi-annual valuation of the Company's common stock was delayed due to the then uncertainty surrounding the refinancing of the Company's outstanding debt. The ESOP trustee, the board of directors and executive management team believed that it was in the best interest of the ESOP participants to delay the valuation until the framework of the refinancing transactions was announced. The valuation was completed in December of 2013. The Company estimates that the aggregate ESOP repurchase obligations for the next five years is approximately $14 million.
			Alion management determines, and the Board of Directors' Audit and Finance Committee reviews, the reasonableness of Alion's recorded redeemable common stock liability. The Audit and Finance Committee considers various factors in its review, including in part, the ESOP valuation report and the share price selected by the ESOP Trustee. Management considers the share price selected by the ESOP Trustee along with other factors in estimating Alion's aggregate liability for outstanding redeemable common stock.
			A limited number of participants who beneficially acquired shares of Alion common stock on December 20, 2002, can sell such shares distributed from their accounts at the greater of $10.00 or the current estimated fair value share price. Although the Company and the ESOP retain the right to delay distributions consistent with the terms of the Plan, and to control the circumstances of future distributions, eventual redemption of shares of Alion common stock is deemed to be outside the Company's control.

Accounts_Receivable1

Accounts Receivable	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Receivables [Abstract]	'							'
Accounts Receivable	'							'
	(6) Accounts Receivable							(7) Accounts Receivable
	Accounts receivable at December 31, 2013 and September 30, 2013 consisted of the following:							Accounts receivable at September 30 consisted of the following:
		December 31,			September 30,				September 30,
		2013			2013				2013			2012
		(In thousands)							(In thousands)
	Billed receivables and amounts billable as of the balance sheet date	$	104,581		$	102,211		Billed receivables and amounts billable as of the balance sheet date	$	102,211		$	94,028
	Unbilled receivables:							Unbilled receivables:
	Amounts billable after the balance sheet date		28,107			36,693		Amounts billable after the balance sheet date		36,693			48,730
	Revenues recorded in excess of milestone billings on fixed price contracts		3,825			3,289		Revenues recorded in excess of milestone billings on fixed price contracts		3,289			2,666
	Revenues recorded in excess of estimated contract value or funding		17,803			14,605		Revenues recorded in excess of estimated contract value or funding		14,605			18,998
	Retainages and other amounts billable upon contract completion		18,635			19,557		Retainages and other amounts billable upon contract completion		19,557			15,016
	Allowance for doubtful accounts		(3,988	)		(3,751	)	Allowance for doubtful accounts		(3,751	)		(4,145	)
	Total Accounts Receivable	$	168,963		$	172,604		Total Accounts Receivable	$	172,604		$	175,293
	Billed accounts receivable include invoices issued to customers for services performed as of the balance sheet date. Unbilled accounts receivable represent revenue recognized as of the balance sheet date for which Alion has yet to issue invoices to customers. Amounts that are currently billable are expected to be invoiced to customers within the next twelve months. Fixed-price contract revenue in excess of milestone billings is not yet contractually billable. Revenue in excess of contract value or funding is billable when Alion receives contract amendments or modifications. Approximately $135.8 million (79%) and $137.5 million (78%) of contract receivables at December 31, 2013 and September 30, 2013 were from federal government prime contracts.							Billed accounts receivable include invoices issued to customers for services performed as of the balance sheet date. Unbilled accounts receivable represent revenue recognized as of the balance sheet date for which Alion has yet to issue invoices to customers. Amounts that are currently billable are expected to be invoiced to customers within the next twelve months. Fixed-price contract revenue in excess of milestone billings is not yet contractually billable. Revenue in excess of contract value or funding is billable when Alion receives contract amendments or modifications. Approximately $137.5 million (78%) and $138.9 million (77%) of contract receivables at September 30, 2013 and September 30, 2012 were from federal government prime contracts.
	At December 31, 2013, Alion recognized $68.4 million in revenue in excess of billings on uncompleted contracts including approximately $17.8 million for customer-requested work for which the Company had not received contracts or contract modifications. At September 30, 2013, Alion had recognized $74.1 million in revenue in excess of billings on uncompleted contracts including approximately $14.6 million for customer-requested work for which the Company had not received contracts or contract modifications.							At September 30, 2013, Alion recognized $74.1 million in revenue in excess of billings on uncompleted contracts including approximately $14.6 million for customer-requested work for which the Company had not received contracts or contract modifications. At September 30, 2012, Alion had recognized $85.4 million in revenue in excess of billings on uncompleted contracts including approximately $19.0 million for customer-requested work for which the Company had not received contracts or contract modifications.
	Retainages and other unbilled amounts are billable upon contract completion or completion of DCAA audits. In keeping with industry practice, Alion classifies all contract-related accounts receivable as current assets based on contractual operating cycles which frequently exceed one year. Except for $18.6 million at December 31, 2013, the Company expects to invoice and collect unbilled receivables within the next twelve months.							Retainages and other unbilled amounts are billable upon contract completion or completion of DCAA audits. In keeping with industry practice, Alion classifies all contract-related accounts receivable as current assets based on contractual operating cycles which frequently exceed one year. Except for $19.6 million at September 30, 2013, the Company expects to invoice and collect unbilled receivables within the next twelve months.

Property_Plant_and_Equipment1

Property, Plant and Equipment	3 Months Ended								12 Months Ended
	Dec. 31, 2013								Sep. 30, 2013
Property Plant And Equipment [Abstract]	'								'
Property, Plant and Equipment	'								'
	-7	Property, Plant and Equipment							(8) Property, Plant and Equipment
			December 31,			September 30,				September 30,
			2013			2013				2013			2012
			(In thousands)							(In thousands)
	Leasehold improvements		$	12,603		$	12,984		Leasehold improvements	$	12,984		$	12,168
	Equipment and software			35,314			35,203		Equipment and software		35,203			35,562
	Total cost			47,917			48,187		Total cost		48,187			47,730
	Less: accumulated depreciation and amortization			(38,847	)		(38,519	)	Less: accumulated depreciation and amortization		(38,519	)		(37,125	)
	Net Property, Plant and Equipment		$	9,070		$	9,668		Net Property, Plant and Equipment	$	9,668		$	10,605
	Depreciation for fixed assets and leasehold amortization expense was approximately $778 thousand and $788 thousand for the quarters ended December 31, 2013 and 2012.								Depreciation and leasehold amortization expense for fixed assets was approximately $3.3 million, $4.3 million, and $4.4 million for the years ended September 30, 2013, 2012, and 2011.

Goodwill1

Goodwill	3 Months Ended			12 Months Ended
	Dec. 31, 2013			Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'			'
Goodwill	'			'
	-8	Goodwill		(9) Goodwill
	The Company accounts for goodwill and other intangible assets according to ASC 350 Intangibles – Goodwill and Other (ASC 350) which requires that Alion review goodwill at least annually for impairment or more frequently if events or circumstances indicate goodwill might be impaired. The Company performs this review at the end of each fiscal year. As of September 30, 2013, Alion had approximately $398.9 million in goodwill. There were no changes to the goodwill carrying amount for the years ended September 30, 2012 and 2011, nor were there any significant events this year that indicated a potential impairment to goodwill as of September 30, 2013.			The Company accounts for goodwill and other intangible assets according to ASC 350 Intangibles – Goodwill and Other (ASC 350) which requires that Alion review goodwill at least annually for impairment or more frequently if events or circumstances indicate goodwill might be impaired. The Company performs this review at the end of each fiscal year. As of September 30, 2013, Alion had approximately $398.9 million in goodwill. There were no changes to the goodwill carrying amount for the years ended September 30, 2012 and 2011, nor were there any significant events this year that indicated a potential impairment to goodwill as of September 30, 2013.
	Alion operates in one segment and tests goodwill at the reporting unit level. Each of Alion’s two reporting units delivers a similar set of professional engineering, scientific and technical services to a wide array of federal government customers, principally within the Department of Defense. Each reporting unit provides the full range of services Alion offers to customers overall.			Alion operates in one segment and tests goodwill at the reporting unit level. Each of Alion’s two reporting units delivers a similar set of professional engineering, scientific and technical services to a wide array of federal government customers, principally within the Department of Defense. Each reporting unit provides the full range of services Alion offers to customers overall.
	Alion’s management has organized reporting units based on managerial responsibility and administrative structure, contract portfolios, and the availability of discrete financial information. Management evaluates reporting unit financial performance based on contract revenue and non-GAAP operating income. Alion does not maintain reporting unit balance sheets and does not track cash flows by reporting unit.			Alion’s management has organized reporting units based on managerial responsibility and administrative structure, contract portfolios, and the availability of discrete financial information. Management evaluates reporting unit financial performance based on contract revenue and non-GAAP operating income. Alion does not maintain reporting unit balance sheets and does not track cash flows by reporting unit.
	Management identifies reporting units as “sectors” which in turn include lower level business units identified as “groups” consisting of still lower level “operations.” For each business combination, management assigned the goodwill arising from acquisitions to the reporting unit or units expected to benefit from the synergies of that business combination. Coincident with its goodwill determination and purchase price allocation, management assigned assets acquired to reporting units based on the unit or units anticipated to utilize such assets. Management did not allocate to reporting units the liabilities arising from business combinations. Alion’s reporting units are the Engineering and Integration Solutions Sector (EISS) and the Technology, Engineering and Operational Solutions Sector (TEOSS). Management assigned $197.0 million in goodwill to EISS and $201.9 million in goodwill to TEOSS.			Management identifies reporting units as “sectors” which in turn include lower level business units identified as “groups” consisting of still lower level “operations.” For each business combination, management assigned the goodwill arising from acquisitions to the reporting unit or units expected to benefit from the synergies of each business combination. Coincident with its goodwill determination and purchase price allocation, management assigned assets acquired to reporting units based on the unit or units anticipated to utilize such assets. Management did not allocate to reporting units the liabilities arising from business combinations. Alion’s reporting units are the Engineering and Integration Solutions Sector (EISS) and the Technology, Engineering and Operational Solutions Sector (TEOSS). Management assigned $197.0 million in goodwill to EISS and $201.9 million in goodwill to TEOSS.
	In 2013, TEOSS had $477 million in contract revenue and EISS had $371 million in contract revenue. Total contract revenue for all reporting units does not equal Alion’s total reported revenue because reporting unit contract revenue does not include $292 thousand in inter-company eliminations, discounts, and GSA industrial funding fees which the Company does not track by reporting unit.			In 2013, TEOSS had $477 million in contract revenue and EISS had $371 million in contract revenue. In 2012, TEOSS had $435 million in contract revenue EISS had $386 million in contract revenue. Total contract revenue for all reporting units does not equal Alion’s total reported revenue because reporting unit contract revenue does not include the effects of inter-company eliminations, discounts and GSA industrial funding fees that the Company does not track by reporting unit. These amounts were $292 thousand in 2013 and $703 thousand in 2012.
	Management applied the guidance in ASC 350 and the related guidance in ASC Topic 280 Segment Reporting to analyze Alion’s reporting units to determine the appropriate level at which to test goodwill for potential impairment. The Company employs a reasonable, supportable and consistent method to assign goodwill to reporting units expected to benefit from the synergies arising from acquisitions. Alion determined reporting unit goodwill in a manner similar to the way it determines goodwill in a purchase allocation by using fair value to determine reporting unit purchase price, assets, liabilities and goodwill. Reporting unit residual fair value after this allocation is the implied fair value of reporting unit goodwill. The Company allocates the goodwill related to acquisitions on a specific identification basis consistent with reporting unit structure.			Management applied the guidance in ASC 350 and the related guidance in ASC Topic 280 Segment Reporting to analyze Alion’s reporting units to determine the appropriate level at which to test goodwill for potential impairment. The Company employs a reasonable, supportable and consistent method to assign goodwill to reporting units expected to benefit from the synergies arising from acquisitions. Alion determined reporting unit goodwill in a manner similar to the way it determines goodwill in a purchase allocation by using fair value to determine reporting unit purchase price, assets, liabilities and goodwill. Reporting unit residual fair value after this allocation is the implied fair value of reporting unit goodwill. The Company allocates the goodwill related to acquisitions on a specific identification basis consistent with reporting unit structure.
	The Company performs its own independent analysis to determine whether goodwill is potentially impaired. Management performs a discounted cash flow analysis to determine the fair value of each reporting unit. The Company compares the aggregated fair value per the discounted cash flow model to the fair value indicated by the market multiples used in the stock valuation. Management independently determines the rates and assumptions it uses to: perform its goodwill impairment analysis; assess the probability of future contracts and revenue; and evaluate the recoverability of goodwill. At September 30, 2013, executed contract backlog was approximately 2.6 times trailing twelve month revenue.			The Company performs its own independent analysis to determine whether goodwill is potentially impaired. Management performs a discounted cash flow analysis to determine the fair value of each reporting unit. The Company compares the aggregated fair value per the discounted cash flow model to the fair value indicated by the market multiples used in the stock valuation. Management independently determines the rates and assumptions it uses to: perform its goodwill impairment analysis; assess the probability of future contracts and revenue; and evaluate the recoverability of goodwill. At September 2013, executed contract backlog was approximately 2.6 times trailing twelve month revenue. Executed backlog at September 2012 was 2.9 times trailing twelve month revenue.
	Alion’s cash flow analysis depends on several significant management inputs and assumptions. Management uses observable inputs, rates and assumptions generally consistent with those used by the independent third party to prepare the valuation report for the ESOP Trustee. However, management’s sensitivity analyses also incorporated a more conservative range of growth assumptions in addition to assumptions generally consistent with those used by the independent third party to prepare the valuation report for the ESOP Trust. These sensitivity analyses are designed to stress management’s best estimate of the Company’s financial forecast for purposes of understanding whether a reasonable decline in growth would cause the associated expected discounted cash flows to fall below the reporting units’ carrying value. Management’s cash flow analysis includes the following significant inputs and assumptions: estimated future revenue and revenue growth; estimated future operating margins and EBITDA; observable market multiples for comparable companies; and a discount rate management believes is consistent with a market-based weighted average cost of capital. Management includes EBITDA in its analysis in order to use publicly available valuation data.			Alion’s cash flow analysis depends on several significant management inputs and assumptions. Management uses observable inputs, rates and assumptions generally consistent with those used by the independent third party to prepare the valuation report for the ESOP Trustee. However, management’s sensitivity analyses also incorporated a more conservative range of growth assumptions in addition to assumptions generally consistent with those used by the independent third party to prepare the valuation report for the ESOP Trust. These sensitivity analyses are designed to stress management’s best estimate of the Company’s financial forecast for purposes of understanding whether a reasonable decline in growth would cause the associated expected discounted cash flows to be below the reporting units’ carrying value. Management’s cash flow analysis includes the following significant inputs and assumptions: estimated future revenue and revenue growth; estimated future operating margins and EBITDA; observable market multiples for comparable companies; and a discount rate consistent with a market-based weighted average cost of capital. Management includes EBITDA in its analysis in order to use publicly available valuation data.
	In Alion’s impairment testing in fiscal 2013, market multiples for trailing twelve month EBITDA for comparable companies (publicly traded professional services government contractors) ranged from a low of 7.6 to a high of 18.2, with a median value of 13.4. Market multiples for trailing twelve month revenue ranged from a low of 0.30 to a high of 3.01, with a median value of 1.36. Management based its goodwill impairment testing valuation on discounted cash flows, and revenue and EBITDA multiples. Management discounted median market multiples by approximately 30% to reflect Alion’s recent financial performance compared to its peers and the significant uncertainties in the professional services government contracting marketplace likely to adversely affect future financial performance. Management used a weighted average cost of capital rate of 13.0% derived from market-based inputs, the tax-effected interest cost of Alion’s outstanding debt and a hypothetical market participant capital structure. Management estimates future years’ EBITDA based on Alion’s reporting units’ historical adjusted EBITDA as a percentage of revenue. To the extent that management’s analysis included forecasts of future revenue growth, management based such estimates on existing contract backlog, recent contract wins, current year performance and new business opportunities. Management analyzed goodwill for impairment using a range of near-term growth values of 0-4% and a range of 0-4% for longer-term out year forecasts.
	There were no changes to the methods used to evaluate goodwill in prior periods. Changes in one or more inputs could materially alter the calculation of Alion’s enterprise fair value and thus the Company’s determination of whether its goodwill is potentially impaired. A hypothetical 10% increase or decrease in the weighted average cost of capital rate at September 30, 2013, would have produced a corresponding approximate 5.7% decrease and 6.9% increase in estimated enterprise value. Alion’s enterprise value based on EBITDA multiples from mergers and acquisitions in the government services market place was approximately 26% higher than discounted cash flow enterprise value at September 30, 2013.			In Alion’s impairment testing in fiscal 2013, market multiples for trailing twelve month EBITDA for comparable companies (publicly traded professional services government contractors) ranged from a low of 7.6 to a high of 18.2, with a median value of 13.4. Market multiples for trailing twelve month revenue ranged from a low of 0.30 to a high of 3.01, with a median value of 1.36. Management based its goodwill impairment testing valuation on discounted cash flows, and revenue and EBITDA multiples. Management discounted median market multiples by approximately 30% to reflect Alion’s recent financial performance compared to its peers and the significant uncertainties in the professional services government contracting marketplace likely to adversely affect future financial performance. Management used a weighted average cost of capital rate of 13.0% derived from market-based inputs, the tax-effected interest cost of Alion’s outstanding debt and a hypothetical market participant capital structure. Management estimates future years’ EBITDA based on Alion’s reporting units’ historical adjusted EBITDA as a percentage of revenue. To the extent that management’s analysis included forecasts of future revenue growth, management based such estimates on existing contract backlog, recent contract wins, current year performance and new business opportunities. Management analyzed goodwill for impairment using a range of near-term growth values of 0-4% and a range of 0-4% for longer-term out year forecasts.
	Management reviews the Company’s internally-computed enterprise fair value to confirm the reasonableness of the internal analysis and compares the results of its independent analysis with the results of the independent third party valuation report prepared for the ESOP Trustee. Management compares each reporting unit’s carrying amount to its estimated fair value. If a reporting unit’s carrying value exceeds its estimated fair value, the Company compares the reporting unit’s goodwill carrying amount with the corresponding implied fair value of its goodwill. If the carrying amount of reporting unit goodwill exceeds its fair value, the Company recognizes an impairment loss to the extent that the carrying amount of goodwill exceeds implied fair value. Alion performs impairment testing on an enterprise value basis as there is no public market for the Company’s common stock.			In Alion’s impairment testing in fiscal 2012, market multiples for trailing twelve month EBITDA for comparable companies (publicly traded professional services government contractors) ranged from a low of 5.6 to a high of 18.2, with a median value of 12.8. Market multiples for trailing twelve month revenue ranged from a low of 0.3 to a high of 3.02, with a median value of 1.32. Management based its goodwill impairment testing valuation on discounted cash flows, and revenue and EBITDA multiples. Management discounted median market multiples by 14%-40% to reflect Alion’s recent financial performance compared to its peers and the significant uncertainties in the professional services government contracting marketplace likely to adversely affect future financial performance. Management used a weighted average cost of capital rate of 12.5% derived from market-based inputs, the tax-effected interest cost of Alion’s outstanding debt and a hypothetical market participant capital structure. Management estimates future years’ EBITDA based on Alion’s historical adjusted EBITDA as a percentage of revenue. To the extent that management’s analysis included forecasts of future revenue growth, management based such estimates on existing contract backlog, recent contract wins, current year performance and new business opportunities. Management analyzed goodwill for impairment using a range of near-term growth values of 0-1% and a range of 0-2% for longer-term out year forecasts.
	Management determined that, on an enterprise value basis, Alion’s reporting units have positive carrying value. In reviewing its discounted cash flow analysis prepared for testing goodwill for potential impairment, management considered macroeconomic and other conditions such as:			There were no changes to the methods used to evaluate goodwill in prior periods. Changes in one or more inputs could materially alter the calculation of Alion’s enterprise fair value and thus the Company’s determination of whether its goodwill is potentially impaired. A hypothetical 10% increase or decrease in the weighted average cost of capital rate at September 30, 2013, would have produced a corresponding approximate 5.7% decrease and 6.9% increase in estimated enterprise value. Alion’s enterprise value based on EBITDA multiples from mergers and acquisitions in the government services market place was approximately 26% higher than discounted cash flow enterprise value at September 30, 2013.
				Management reviews the Company’s internally-computed enterprise fair value to confirm the reasonableness of the internal analysis and compares the results of its independent analysis with the results of the independent third party valuation report prepared for the ESOP Trustee. Management compares each reporting unit’s carrying amount to its estimated fair value. If a reporting unit’s carrying value exceeds its estimated fair value, the Company compares the reporting unit’s goodwill carrying amount with the corresponding implied fair value of its goodwill. If the carrying amount of reporting unit goodwill exceeds its fair value, the Company recognizes an impairment loss to the extent that the carrying amount of goodwill exceeds implied fair value. Alion performs impairment testing on an enterprise value basis as there is no public market for the Company’s common stock.
		•	the deterioration in general economic conditions arising from federal budget deficits;	Management determined that, on an enterprise value basis, Alion’s reporting units have positive carrying value. In reviewing its discounted cash flow analysis prepared for testing goodwill for potential impairment, management considered macroeconomic and other conditions such as:
		•	Industry and market concerns about the effects of sequestration and federal budget deficits on future Department of Defense procurement actions;		•	the deterioration in general economic conditions arising from federal budget deficits;
		•	Alion’s credit rating and its potential for limiting future access to capital;		•	Defense and aerospace industry and market concerns about the effects of sequestration and federal budget deficits on future Department of Defense procurement actions;
		•	An increase in market risks		•	Alion’s credit rating and its potential for limiting future access to capital;
					•	An increase in market risks
		•	A higher discount rate for valuing estimated future cash flows;
					•	A higher discount rate for valuing estimated future cash flows;
		•	A decline in market-dependent multiples and metrics in both absolute terms and for Alion relative to its peers;
					•	A decline in market-dependent multiples and metrics in both absolute terms and for Alion relative to its peers;
		•	Alion’s fiscal 2013 sales increase; and
					•	Alion’s current year sales increase compared to last year; and
		•	Alion’s success in obtaining $840 million of additional customer contract funding and new contracts from April through September 30, 2013.
	Alion completed its most recent goodwill impairment analysis in the fourth quarter of fiscal year 2013 and concluded no goodwill impairment existed as of September 30, 2013. Management determined the totality of events and circumstances would not have supported a decision to roll forward its prior year goodwill impairment analysis and avoid performing a step one goodwill impairment analysis. Management chose to perform a step one analysis which supported a comparable enterprise value for Alion as of September 30, 2013 compared to September 30, 2012. September 30, 2013 estimated discounted future cash flows decreased less than 1.0% compared to September 30, 2012. The estimated fair value of Alion’s outstanding debt increased approximately 10 percent from September 30, 2012 to September 30, 2013. This was due to shortening maturities and a higher outstanding balance for secured debt and notwithstanding fiscal 2013 unsecured debt redemptions. As a result of changes in Alion’s estimated enterprise fair value and the increased value of Alion’s outstanding debt, the estimated fair value of Alion’s outstanding redeemable common stock declined approximately 50% from September 30, 2012 to September 30, 2013.				•	Alion’s success in obtaining $840 million of additional customer contract funding and new contracts in the past six months.
	As of September 30, 2013, the estimated fair value of each reporting unit exceeded its carrying value. Consistent with prior years’ disclosures, the changes in discounted cash flows for fiscal 2013 compared to fiscal 2012 did not result in an impairment to goodwill. The results of Alion’s step one impairment testing make it unlikely that a reasonably probable change in assumptions would have triggered an impairment. A hypothetical 10% decrease in fair value would not have resulted in impairment to goodwill for either reporting unit or triggered the need to perform additional step two analyses for either reporting unit.			Alion completed its most recent goodwill impairment analysis in the fourth quarter of fiscal year 2013 and concluded no goodwill impairment existed as of September 30, 2013. Management determined the totality of events and circumstances would not have supported a decision to roll forward its prior year goodwill impairment analysis and avoid performing a step one goodwill impairment analysis. Management chose to perform a step one analysis which supported a comparable enterprise value for Alion as of September 2013 compared to September 2012. September 2013 estimated discounted future cash flows decreased less than 1.0% compared to September 2012. The estimated fair value of Alion’s outstanding debt increased approximately 10 percent from September 2012 to September 2013. This was due to shortening maturities and a higher outstanding balance for secured debt and notwithstanding current year unsecured debt redemptions. As a result of changes in Alion’s estimated enterprise fair value and the increased value of Alion’s outstanding debt, the estimated fair value of Alion’s outstanding redeemable common stock declined approximately 50% from September 2012 to September 2013.
				As of September 30, 2013, the estimated fair value of each reporting unit exceeded its carrying value. Consistent with prior years’ disclosures, the changes in discounted cash flows for fiscal 2013 compared to fiscal 2012 did not result in an impairment to goodwill. The results of Alion’s step one impairment testing make it unlikely that a reasonably probable change in assumptions would have triggered an impairment. A hypothetical 10% decrease in fair value would not have resulted in impairment to goodwill for either reporting unit or triggered the need to perform additional step two analyses for either reporting unit.

Intangible_Assets1

Intangible Assets	3 Months Ended																12 Months Ended
	Dec. 31, 2013																Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'																'
Intangible Assets	'																'
	-9	Intangible Assets															(10) Intangible Assets
	Intangible assets consist primarily of contracts acquired through the Anteon and JJMA transactions. The table below shows intangible assets as of December 31, 2013 and September 30, 2013.																The Company accounts for intangible assets according to ASC 350 Intangibles – Goodwill and Other. Intangible assets consist primarily of contracts acquired in the JJMA transaction. The table below shows the intangible assets as of September 30, 2013 and 2012.
			December 31, 2013							September 30, 2013								September 30, 2013							September 30, 2012
			Gross		Accumulated			Net		Gross		Accumulated			Net			Gross		Accumulated			Net		Gross		Accumulated			Net
					Amortization							Amortization								Amortization							Amortization
			(In thousands)															(In thousands)
	Purchased contracts		$	111,635	$	(110,015	)	$	1,620	$	111,635	$	(109,795	)	$	1,840	Purchased contracts	$	111,635		(109,795	)		1,840	$	111,635	$	(106,935	)	$	4,700
	Internal use software and engineering designs			3,182		(3,067	)		115		3,182		(2,982	)		200	Internal use software and engineering designs		3,182		(2,982	)		200		3,182		(2,640	)		542
	Total		$	114,817	$	(113,082	)	$	1,735	$	114,817	$	(112,777	)	$	2,040	Total	$	114,817		(112,777	)		2,040	$	114,817	$	(109,575	)	$	5,242
	The weighted-average remaining amortization period of intangible assets was approximately 18 months at December 31, 2013 and September 30, 2013. Amortization expense was approximately $305 thousand and $1.5 million for the quarters ended December 31, 2013 and 2012. Estimated aggregate amortization expense for the next five years and thereafter is as follows.																The weighted-average remaining amortization period of intangible assets was approximately 20 months at September 30, 2013. Amortization expense was approximately $3.2 million, $6.5 million, and $7.0 million for the years ended September 30, 2013, 2012 and 2011. Estimated aggregate amortization expense for the next five years and thereafter is as follows.
			(In thousands)														Fiscal year ending	(In thousands)
																	September 30,
	2014 (for the remainder of the fiscal year)		$	773													2014		1,079
	2015			737													2015		736
	2016			141													2016		141
	2017			51													2017		51
	2018			33													2018		33
	2019			—
	Thereafter			—														$	2,040
			$	1,735

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Long-Term Debt	'
	(11) Long-Term Debt
	Alion’s current debt structure includes a $35 million revolving credit facility, $329.8 million in Secured Notes ($310 million in initial face value plus $19.8 million in paid in kind (PIK) interest notes issued) and $235 million of Unsecured Notes. Except as noted below, the Company is in compliance with each of the affirmative, negative and financial covenants in its existing debt agreements as of September 30, 2013.
	Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of a potential covenant breach, resulting from an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this covenant. The Company paid no fee for this waiver. Absent the waiver, the Company would not have been able to access its revolving credit facility. At September 30, 2013, the Company had not drawn on the Credit Agreement revolving credit facility. At the date of the waiver, the Company had a balance drawn on the Credit Agreement revolving credit facility. Had the Credit Agreement lenders not granted the waiver, they would have had the right to demand the Company immediately repay any amounts outstanding under the revolving credit facility. The amount drawn on the Credit Agreement revolving credit facility was less than $30 million at the date of the waiver. Therefore, there was no potential cross default on the Company’s other outstanding indebtedness. See also Note 24 – Subsequent Events.
	Credit Agreement
	The Company can use its credit facility for working capital, permitted acquisitions and general corporate purposes. This includes up to $35.0 million in letters of credit and up to $5.0 million in short-term swing line loans. As of September 30, 2013, the Company had $4.0 million in outstanding letters of credit and no balance actually drawn.
	Security. The Credit Agreement is secured by a first priority security interest in all current and future tangible and intangible property of Alion and its guarantor subsidiaries, IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation. In March 2010, Alion and the subsidiary guarantors entered into an Intercreditor Agreement with Wilmington Trust Company and Credit Suisse AG, Cayman Islands Branch to grant Credit Agreement lenders a super priority right of payment with respect to the underlying collateral compared to Secured Note holders’ rights.
	Guarantees. Alion’s Credit Agreement obligations are guaranteed by its subsidiaries, IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation. These subsidiaries also guarantee all the Company’s Secured Note and Unsecured Note obligations (described below).
	Interest and Fees. Alion can choose whether the Credit Agreement loans bear interest at one of two floating rates using either a Eurodollar rate or an alternative base rate. The minimum interest rate is 8.5%. The minimum Eurodollar interest rate is 2.5% plus 600 basis points. The minimum alternate base rate is 3.5% plus 500 basis points.
	Other Fees and Expenses. Each quarter, Alion pays a commitment fee of 175 basis points per year on the prior quarter’s daily unused Credit Agreement balance. The Company paid approximately $533 thousand and $559 thousand in commitment fees for the years ended September 30, 2013 and 2012. Alion pays letter-of-credit issuance and administrative fees, and up to a 25 basis point fronting fee and interest in arrears each quarter on all outstanding letters of credit. The interest rate is based on the Eurodollar loan rate which was 6.0% as of September 30, 2013. The Company also pays an annual agent’s fee.
	Covenants. The Credit Agreement requires Alion to achieve minimum trailing twelve month Consolidated EBITDA levels which increase over the remaining life of the agreement. The required minimum is $63.0 million through September 30, 2013 and $65.5 million through August 22, 2014.
	The Credit Agreement defines Consolidated EBITDA as net income or loss in accordance with GAAP, plus employee compensation expense payments invested in Alion common stock, plus the following items, without duplication, to the extent deducted from or included in net income or loss:
		•		consolidated interest expense;
		•		provision for income taxes;
		•		depreciation and amortization;
		•		cash contributed to the ESOP in respect of Alion’s repurchase liability;
		•		non-cash stock-based and incentive compensation expense;
		•		non-cash ESOP contributions;
		•		any extraordinary losses; and
		•		nonrecurring charges and adjustments included in ESOP valuation reports as prepared by an independent third party.
	To the extent included in net income or loss, the following items, without duplication, are deducted in determining Consolidated EBITDA:
		•		all cash payments on account of reserves, restructuring charges or other cash and non-cash charges added to net
		•		income pursuant to the list above in a previous period;
		•		any extraordinary gains; and
		•		all non-cash items of income.
	The Credit Agreement restricts us from doing any of the following without the prior consent of syndicate lenders that extended more than 50 percent of the aggregate amount of all Credit Agreement loans then outstanding:
		•		incur additional debt other than permitted additional debt;
		•		grant certain liens and security interests;
		•		enter into sale and leaseback transactions;
		•		make certain loans and investments including acquisitions of businesses, other than permitted acquisitions;
		•		consolidate, merge or sell all or substantially all our assets;
		•		pay dividends or distributions other than distributions required by the ESOP Plan or by certain legal requirements;
		•		make certain payments for subordinated indebtedness;
		•		enter into certain transactions with our shareholders and affiliates;
		•		enter into agreements which restrict our ability to incur liens or which restrict the ability of our subsidiaries to pay dividends
		•		change lines of business;
		•		repay subordinated debt before it is due;
		•		redeem or repurchase certain equity;
		•		enter into certain transactions not permitted under ERISA;
		•		change the terms of our other indebtedness or our KSOP in a way materially disadvantageous to us;
		•		make more than $8 million in capital expenditures in any fiscal year;
		•		pay certain earn-outs in connection with permitted acquisitions; or
		•		change our fiscal year.
	The Credit Agreement contains customary events of default including, without limitation:
		•		breach of representations and warranties;
		•		payment default;
		•		uncured covenant breaches;
		•		default under certain other debt exceeding an agreed amount;
		•		bankruptcy and certain insolvency events;
		•		incurrence of a civil or criminal liability in excess of $5 million of Alion or any subsidiary arising from a government investigation;
		•		unstayed judgments in excess of an agreed amount;
		•		failure of any Credit Agreement guarantee to be in effect;
		•		failure of the security interests to be valid, perfected, first priority security interests in the collateral;
		•		notice of debarment, suspension or termination under a material government contract;
		•		actual termination of a material contract due to alleged fraud, willful misconduct, negligence, default or any other wrongdoing;
		•		certain uncured defaults under our material contracts;
		•		certain ERISA violations;
		•		imposition on the ESOP Trust of certain taxes in excess of an agreed amount;
		•		final determination the ESOP is not a qualified plan;
		•		so long as any Secured Notes remain outstanding, the Intercreditor Agreement shall fail to be effective;
		•		a borrowing which would cause us to exceed a certain cash balance limit;
		•		failure to provide within 90 days of fiscal year-end, consolidated, comparative financial statements audited by an independent public accountant of recognized national standing with an opinion of such accountant that shall not include a “going concern” explanatory note or similar limitation, or
		•		a change of control (as defined below).
	Under the Credit Agreement a change of control generally occurs when, before Alion lists its common stock to trade on a national securities exchange and obtains at least $35 million in net proceeds from an underwritten public offering, the ESOP Trust fails to own at least 51 percent of Alion’s outstanding equity interests, or, after such a qualified public offering, any person or group other than the ESOP Trust owns more than 37.5 percent of Alion’s outstanding equity interests. A change of control may also occur if a majority of the seats (other than vacant seats) on Alion’s Board of Directors shall at any time be occupied by persons who were neither nominated by the board nor were appointed by directors so nominated. A change of control may also occur if a change of control occurs under any of Alion’s material debt including the Secured and Unsecured Note Indentures.
Alion depends heavily on federal government contracts; delays in the federal budget process, reduced federal spending, budget cuts, sequestration and fiscal and political uncertainties could adversely affect Alion’s revenue for the coming fiscal year. Despite uncertainties in the government contracting professional services marketplace, particularly the prospect of sequestration and/or Department of Defense programmatic and budgetary cuts, management believes Alion will be able to generate sufficient revenue and EBITDA for the remaining life of the Credit Agreement and the Company will be able to comply with financial and non-financial covenants in the Credit Agreement.
If Alion were unable to meet a Credit Agreement covenant because of a revenue shortfall or for any other reason, the Company could seek another covenant waiver or seek to negotiate a Credit Agreement amendment. Management can provide no assurance that Alion would be able to obtain a requested covenant waiver or amend the Credit Agreement on favorable terms.
Secured Notes
In March 2010, Alion issued and sold $310 million of its private units (Units) to Credit Suisse, which informed the Company it had resold most of the Units to qualified institutional buyers. Each of the 310,000 Units consisted of $1,000 in face value of Alion’s private 12% senior secured notes (Secured Notes) and a warrant to purchase 1.9439 shares of Alion common stock. On September 2, 2010, Alion exchanged the private Secured Notes for publicly tradable Secured Notes with the same terms.
Security. The Secured Notes are secured by a first priority security interest in all current and future tangible and intangible property of Alion and its guarantor subsidiaries, IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation. The Secured Notes are senior obligations of Alion and rank pari passu in right of payment with existing and future senior debt, including the Credit Agreement, except to the extent that the Intercreditor Agreement provides Credit Agreement lenders with a super priority right of payment with respect to the underlying collateral.
Guarantees. The Company’s obligations under the Secured Notes are guaranteed by the Company’s subsidiaries, IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation.
Interest and Fees. The Secured Notes bear interest at 12% per year; 10% is payable in cash and 2% increases the Secured Note principal (PIK Interest). Interest is payable semi-annually in arrears on May 1 and November 1. Alion pays interest to holders of record as of the immediately preceding April 15 and October 15. The Company must pay interest on overdue principal or interest at 13% per annum to the extent lawful. The Secured Notes mature November 1, 2014.
Covenants. As of September 30, 2013, Alion was in compliance with the covenants set forth in the Indenture governing its 12% Secured Notes (Secured Note Indenture). The Secured Note Indenture does not contain any financial covenants.
A Secured Note Indenture covenant restricts our ability to incur additional debt. Defined terms in the Secured Note Indenture include: Net Available Cash, Total Assets, Restricted Subsidiaries, Indebtedness, Adjusted EBITDA and Consolidated Interest Expense. Alion and its Restricted Subsidiaries may not issue, incur, assume, guarantee, or otherwise become liable for any debt unless our Adjusted EBITDA to Consolidated Interest Expense ratio is greater than 2.0 to 1.0. Adjusted EBITDA under the Secured Note Indenture differs from Consolidated EBITDA as defined in our Credit Agreement. Adjusted EBITDA is less than Consolidated EBITDA because it does not include employee investments in Alion common stock. Our Adjusted EBITDA to Consolidated Interest Expense ratio was 0.91 to 1.0 as of September 30, 2013 ($69.0 million in Adjusted EBITDA to $75.7 million in Consolidated Interest Expense). Our ratio was 0.93 to 1.0 as of September 30, 2012 ($69.3 million in Adjusted EBITDA to $74.9 million in Consolidated Interest Expense). Even if Adjusted EBITDA is not at least two times Consolidated Interest Expense, we may incur other permitted debt including:
	•		debt pursuant to certain agreements up to $25 million;
	•		permitted inter-company debt;
	•		the Secured Notes and any public notes exchanged for those notes;
	•		debt pre-dating the Secured Notes;
	•		permitted debt of acquired subsidiaries;
	•		permitted refinancing debt;
	•		hedging agreement debt;
	•		performance, bid, appeal and surety bonds and completion guarantees;
	•		ordinary course insufficient funds coverage;
	•		permitted refinancing debt guarantees;
	•		working capital debt of non-U.S. subsidiaries;
	•		debt for capital expenditures, and capital and synthetic leases up to $25 million in the aggregate and 2.5% of Alion’s Total Assets;
	•		permitted subordinated debt of Alion or any Restricted Subsidiary to finance a permitted acquisition, certain permitted ESOP transactions and refinancing debt of acquired non-U.S. subsidiaries up to $35 million in the aggregate;
	•		letter of credit reimbursement obligations;
	•		certain agreements in connection with a business disposition provided liabilities incurred in connection therewith do not exceed the cash and non-cash proceeds received and are not reflected on the Company’s balance sheet;
	•		certain deferred compensation agreements; and
	•		certain other debt up to $20 million.
The Secured Note Indenture has a covenant that restricts our ability to declare and pay any cash dividend or other distribution related to any equity interest in Alion, repurchase or redeem any equity interest of Alion, repurchase or redeem the Unsecured Notes or other subordinated debt, or make certain investments. However, within certain limits we may make such payments in limited amounts if Adjusted EBITDA is at least two times Consolidated Interest Expense. Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0, we may make or pay:
	•		such payments out of substantially concurrent contributions of equity and substantially concurrent incurrences of permitted debt;
	•		certain limited and permitted dividends;
	•		certain repurchases of the Company’s equity securities deemed to occur upon exercise of stock options or warrants;
	•		cash payments in lieu of the issuance of fractional shares in connection with the exercise of warrants, options or other securities convertible into or exchangeable for our equity securities;
	•		the required Secured Note premium payable on a change of control;
	•		certain permitted inter-company subordinated obligations;
	•		certain repurchases and redemptions of subordination obligations of the Company or a Subsidiary Guarantor from Net Available Cash (as defined in the Secured Note Indenture);
	•		repurchases of subordinated obligations in connection with an asset sale to the extent required by the Secured Note Indenture;
	•		certain permitted ESOP transactions;
	•		long-term incentive plan payments to our directors, officers and employees, subject to a $3 million annual cap that may increase annually;
	•		any purchase, repurchase, redemption, defeasance or other acquisition or retirement for value of the Unsecured Notes, up to an aggregate amount of $10 million; and
	•		certain other payments not exceeding $10 million in the aggregate.
The Secured Note Indenture restricts our ability to engage in other transactions including restricting our subsidiaries from making distributions and paying dividends to parents, merging or selling all or substantially all our assets, issuing certain subsidiary equity securities, engaging in certain transactions with affiliates, incurring liens, entering into sale lease-back transactions and engaging in business unrelated to our business when we issued the Secured Notes.
Events of Default. The Secured Note Indenture contains customary events of default, including:
	•		payment default on interest obligations when due;
	•		payment default on principal at maturity;
	•		uncured covenant breaches;
	•		default under an acceleration of certain other debt exceeding $30 million;
	•		bankruptcy and certain insolvency events;
	•		judgment for payment in excess of $30 million entered against the Company or any material subsidiary that remains outstanding for a period of 60 days and is not discharged, waived or stayed;
	•		failure of any Secured Note guarantee to be in effect or any subsidiary guarantor’s denial or disaffirmation of its guaranty obligations; and
	•		failure of any Secured Note security interest to constitute a valid and perfected lien with its applicable priority after a permitted cure period.
Change of Control. Upon a change in control, each Secured Note holder has the right to require Alion repurchase its notes in cash for 101% of principal plus accrued and unpaid interest. Any of the following events constitutes a change in control:
	•		subject to certain exceptions, a person, other than the ESOP Trust, is or becomes the beneficial owner, directly or indirectly, of more than 35% of the total voting power or voting stock of Alion;
	•		individuals who constituted Alion’s board of directors on March 22, 2010, (or individuals who were elected or nominated by them, or directors subsequently nominated or elected by them) cease for any reason to constitute a majority of the Company’s board of directors;
	•		the adoption of a plan relating to Alion’s liquidation or dissolution; and
	•		subject to certain exceptions, the merger or consolidation of the Company with or into another person or the merger of another person with or into the Company, or the sale of all or substantially all the assets of Alion to another person.
Optional Redemption. From April 1, 2013 through September 30, 2013, the Company was permitted to redeem all or a portion of the Secured Notes at 105% of principal, plus accrued and unpaid interest to the redemption date. From October 1, 2013 through March 31, 2014 the redemption price is 103% of principal, plus accrued and unpaid interest to the redemption date. After March 31, 2014, the Company is not required to pay a redemption premium.
Unsecured Notes
In February 2007, Alion issued and sold $250.0 million of its private 10.25% senior unsecured notes due February 1, 2015 (Unsecured Notes) to Credit Suisse, which informed the Company it had resold most of the notes to qualified institutional buyers. In June 2007, Alion exchanged the private Unsecured Notes for publicly tradable Unsecured Notes with the same terms. IPS, CATI, METI, JJMA, BMH, WCI, WCGS, MA&D and Alion International Corporation guarantee the Unsecured Notes. From time to time, Alion has repurchased some of its outstanding Unsecured Notes in open market transactions. As of September 30, 2013, the Company had repurchased $15 million worth of Unsecured Notes: $2 million in November 2010; $3 million in June 2011, $5 million in June 2013 and an additional $5 million in July 2013. The Company recognized a gain on debt extinguishment for each Secured Note repurchase. In fiscal 2013, the Company recognized a $3.9 million gain; there were no debt extinguishments in fiscal 2012. In 2011, the Company recognized a $939 thousand debt extinguishment gain.
Interest and Fees. The Unsecured Notes bear interest at 10.25% per year, payable semi-annually in arrears on February 1 and August 1. Alion pays interest to holders of record as of the immediately preceding January 15 and July 15. The Company must pay interest on overdue principal or interest at 11.25% per annum to the extent lawful.
Covenants. There are no financial covenants in the Unsecured Note Indenture. As of September 30, 2013, we were in compliance with Unsecured Note Indenture non-financial covenants.
A covenant in the Unsecured Note Indenture restricts our ability to incur additional debt. Defined terms in the Unsecured Note Indenture include: Net Available Cash, Total Assets, Restricted Subsidiaries, Indebtedness, Adjusted EBITDA and Consolidated Interest Expense. Alion and its Restricted Subsidiaries may not issue, incur, assume, guarantee, or otherwise become liable for any indebtedness unless our Adjusted EBITDA to Consolidated Interest Expense ratio is greater than 2.0 to 1.0. Adjusted EBITDA under the Unsecured Note Indenture differs from Consolidated EBITDA as defined in our Credit Agreement. Adjusted EBITDA is less than Consolidated EBITDA because it does not include employee investments in Alion common stock. Our Adjusted EBITDA to Consolidated Interest Expense ratio was 0.91 to 1.0 as of September 30, 2013 ($69.0 million in Adjusted EBITDA to $75.7 million in Consolidated Interest Expense). Our ratio was 0.93 to 1.0 as of September 30, 2012 ($69.3 million in Adjusted EBITDA to $74.9 million in Consolidated Interest Expense). Even if Adjusted EBITDA is not at least two times Consolidated Interest Expense, we may incur other permitted debt including:
	•		debt pursuant to our now terminated Term B Credit Facility and certain other contracts up to $360 million less principal repayments made under that indebtedness;
	•		permitted inter-company debt;
	•		the Unsecured Notes and any public notes exchanged for those notes;
	•		debt pre-dating the Unsecured Notes;
	•		permitted debt of acquired subsidiaries;
	•		permitted refinancing debt;
	•		hedging agreement debt;
	•		performance, bid, appeal and surety bonds and completion guarantees;
	•		ordinary course insufficient funds coverage;
	•		permitted refinancing debt guarantees;
	•		working capital debt of non-U.S. subsidiaries;
	•		debt for capital expenditures, capital and synthetic leases up to $25 million in the aggregate and 2.5% of Alion’s Total Assets;
	•		permitted subordinated debt of Alion or any Restricted Subsidiary to finance a permitted acquisition, certain permitted ESOP transactions and refinancing debt of acquired non-U.S. subsidiaries up to $35 million in the aggregate;
	•		letters of credit reimbursement obligations;
	•		certain agreements in connection with the disposition of a business provided liabilities incurred in connection therewith do not exceed the cash and non-cash proceeds received and are not reflected on the Company’s balance sheet;
	•		certain deferred compensation agreements; and
	•		certain other debt up to $35 million.
The Unsecured Note Indenture has a covenant that restricts our ability to declare and pay any cash dividend or other distribution with regard to any equity interest in the Company, make any repurchase or redemption of any equity interest in Alion, repurchase or redeem subordinated debt, and make certain investments. However, within certain limits we may make such payments in limited amounts if Adjusted EBITDA is at least two times Consolidated Interest Expense. Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0, we may make or pay:
	•		such payments out of substantially concurrent contributions of equity and substantially concurrent incurrences of permitted debt;
	•		certain limited and permitted dividends;
	•		certain repurchases of the Company’s equity securities deemed to occur upon exercise of stock options or warrants;
	•		cash payments in lieu of the issuance of fractional shares for the exercise of warrants, options or other securities convertible into or exchangeable for our equity securities;
	•		the required Unsecured Note premium payable on a change of control;
	•		certain permitted inter-company subordinated obligations;
	•		certain repurchases and redemptions of subordination obligations of the Company or a Subsidiary Guarantor from Net Available Cash;
	•		repurchases of subordinated obligations in connection with an asset sale to the extent required by the Indenture;
	•		repurchase of common stock from former Alion Joint Spectrum Center employees;
	•		certain permitted transactions with the ESOP not exceeding $25 million in the aggregate; and
	•		certain other payments not exceeding $30 million in the aggregate.
The Unsecured Note Indenture restricts the Company’s ability to engage in other transactions including restricting our subsidiaries from making distributions and paying dividends to parents, merging or selling all or substantially all our assets, issuing certain subsidiary equity securities, engaging in certain transactions with affiliates, incurring liens, entering into sale lease-back transactions and engaging in business unrelated to our business when we issued the Unsecured Notes.
Events of Default. The Unsecured Note Indenture contains customary events of default, including:
	•		payment default on interest obligations when due;
	•		payment default on principal at maturity;
	•		uncured covenant breaches;
	•		default under an acceleration of certain other debt exceeding $30 million;
	•		certain bankruptcy and insolvency events;
	•		judgment for payment in excess of $30 million entered against the Company or any material subsidiary that remains outstanding for a period of 60 days and is not discharged, waived or stayed; and
	•		failure of any Unsecured Note guarantee or any subsidiary guarantor’s denial or disaffirmation of its guaranty obligations.
Change of Control. Upon a change in control, each Unsecured Note holder has the right to require Alion repurchase its notes in cash for 101% of principal plus accrued and unpaid interest. Any of the following events constitutes a change in control:
	•		subject to certain exceptions, a person, other than the ESOP Trust, is or becomes the beneficial owner, directly or indirectly, of more than 35% of the total voting power or voting stock of Alion;
	•		individuals who constituted Alion’s board of directors on February 8, 2007, (or individuals who were elected or nominated by them, or individuals who were elected or nominated by them) cease for any reason to constitute a majority of the Company’s board of directors;
	•		adoption of a plan relating to Alion’s liquidation or dissolution; and
	•		subject to certain exceptions, Alion’s merger or consolidation with or into another person or the merger of another person with or into Alion, or the sale of all or substantially all our assets to another person.
Optional Redemption. Beginning February 1, 2013, we may redeem all or a portion of the Unsecured Notes at par plus accrued and unpaid interest to the redemption date. Alion will need to refinance some if not all its senior debt prior to maturity in November 2014 and February 2015 when the Company will have to payout more than $600 million over a three-month period. We are uncertain if Alion will be able to refinance these obligations or if refinancing terms will be favorable. The Company continues to work with Goldman Sachs and Wells Fargo in its refinancing efforts.
		September 30,
		2013		2012
		(In thousands)
Secured Notes			13,741		13,470
Unsecured Notes		$	4,017	$	4,188
Total		$	17,758	$	17,658
As of September 30, 2013, Alion must make the following principal repayments (face value) for its outstanding debt. Face value exceeds carrying value which includes debt issue costs. Debt issue costs include the unamortized balances of: original issue discount; third-party debt issue costs; and the initial fair value of common stock warrants issued in connection with the Secured Notes
		2014		2015		Total
Secured Notes and PIK Interest (1)		$	—	$	339,788	$	339,788
Unsecured Notes (2)			—		235,000		235,000
Total Principal Payments		$	—	$	574,788	$	574,788
1	The Secured Notes due November 2014 include $310 million of debt issued in March 2010 and an estimated $29.8 million in PIK interest added to principal over the life of the notes. As of September 30, 2013, the $322.3 million carrying value on the face of the balance sheet included $310 million in principal, $19.8 million in PIK notes issued; $2.7 million in accrued PIK interest and is net of $10.3 million in aggregate unamortized debt issue costs. Initial debt issue costs consist of $7.7 million in original issue discount, $13.5 million in third-party costs and $20.8 million for the Secured Note warrants’ initial fair value.
2	As of September 30, 2013, the Unsecured Notes due February 2015 include $235 million in principal and $1.2 million in unamortized debt issue costs (initially $7.1 million). The Company repurchased $10 million in Unsecured Notes in 2013 and $5 million in Unsecured Notes in 2011.

Fair_Value_Measurement1

Fair Value Measurement	3 Months Ended														12 Months Ended
	Dec. 31, 2013														Sep. 30, 2013
Fair Value Disclosures [Abstract]	'														'
Fair Value Measurement	'														'
	-11	Fair Value Measurement													(12) Fair Value Measurement
	Alion applies ASC 820 – Fair Value Measurements and Disclosures in determining the fair value to be disclosed for financial and nonfinancial assets and liabilities. The Company has no assets or liabilities, other than its redeemable common stock, which it is required to report at fair value. Valuation techniques utilized in the fair value measurement of assets and liabilities for each period presented were unchanged from prior practice.														Alion applies ASC 820 – Fair Value Measurements and Disclosures in determining the fair value to be disclosed for financial and nonfinancial assets and liabilities. The Company has no assets or liabilities, other than its redeemable common stock, which it is required to report at fair value. Valuation techniques utilized in the fair value measurement of assets and liabilities for each period presented were unchanged from prior practice.
	ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. It establishes a fair value hierarchy and a framework which requires categorizing assets and liabilities into one of three levels based on the assumptions (inputs) used in valuing the asset or liability. Level 1 provides the most reliable measure of fair value, while Level 3 generally requires significant management judgment. Level 1inputs are unadjusted, quoted market prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in inactive markets. Level 3 inputs include unobservable inputs that are supported by little, infrequent, or no market activity and reflect management’s own assumptions about inputs used in pricing the asset or liability. The Company uses the following valuation techniques to measure fair value.														ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in
	Level 1 primarily consists of financial instruments, such as overnight bank re-purchase agreements or money market mutual funds whose value is based on quoted market prices published by financial institutions, exchange funds, exchange-traded instruments and listed equities.														an orderly transaction between market participants at the measurement date. It establishes a fair value hierarchy and a framework which requires categorizing assets and liabilities into one of three levels based on the assumptions (inputs) used in valuing the asset or liability. Level 1 provides the most reliable measure of fair value, while Level 3 generally requires significant management judgment. Level 1inputs are unadjusted, quoted market prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in inactive markets. Level 3 inputs include unobservable inputs that are supported by little, infrequent, or no market activity and reflect management’s own assumptions about inputs used in pricing the asset or liability. The Company uses the following valuation techniques to measure fair value.
	Level 2 assets include U.S. Government and agency securities whose valuations are based on market prices from a variety of industry-standard data providers or pricing that considers various assumptions, including time value, yield curve, volatility factors, credit spreads, default rates, loss severity, current market and contractual prices for the underlying instruments, and broker and dealer quotes. All are observable in the market or can be derived principally from or corroborated by observable market data for which the Company can obtain independent external valuation information.														Level 1 primarily consists of financial instruments, such as overnight bank re-purchase agreements or money market mutual funds whose value is based on quoted market prices published by financial institutions, exchange funds, exchange-traded instruments and listed equities.
															Level 2 assets include U.S. Government and agency securities whose valuations are based on market prices from a variety of industry-standard data providers or pricing that considers various assumptions, including time value, yield curve, volatility factors, credit spreads, default rates, loss severity, current market and contractual prices for the underlying instruments, and broker and dealer quotes. All are observable in the market or can be derived principally from or corroborated by observable market data for which the Company can obtain independent external valuation information.
	Level 3 consists of unobservable inputs. Assets and liabilities are considered Level 3 when their fair value inputs are unobservable or not available, including situations involving limited market activity, where determination of fair value requires significant judgment or estimation.														Level 3 consists of unobservable inputs. Assets and liabilities are considered Level 3 when their fair value inputs are unobservable or not available, including situations involving limited market activity, where determination of fair value requires significant judgment or estimation.
	The table below sets out the face value, net carrying value and fair value of Alion’s Secured and Unsecured Notes. The fair values disclosed below are based on quoted market prices for Alion’s outstanding notes. This is a Level 2 measurement.
															The table below sets out the face value, net carrying value and fair value of Alion’s Secured and Unsecured Notes. The fair values disclosed below are based on quoted market prices for Alion’s outstanding notes. This is a Level 2 measurement.
			December 31, 2013						September 30, 2013
			(In thousands)													September 30, 2013						September 30, 2012
			Secured			Unsecured			Secured			Unsecured				(In thousands)
			Notes			Notes			Notes			Notes				Senior			Senior			Senior			Senior
	Face value of original notes outstanding		$	310,000		$	235,000		$	310,000		$	235,000			Secured			Unsecured			Secured			Unsecured
	PIK interest notes issued			23,086			—			19,788			—			Notes			Notes			Notes			Notes
															Face value of original notes outstanding	$	310,000		$	235,000		$	310,000		$	245,000
	Face value of outstanding notes		$	333,086		$	235,000		$	329,788		$	235,000		PIK interest notes issued		19,788			—			13,293			—
	PIK interest notes to be issued			1,111			—			2,748			—
															Face value of outstanding notes	$	329,788		$	235,000		$	323,293		$	245,000
	Face value of notes outstanding and notes to be issued		$	334,197		$	235,000		$	332,536		$	235,000		PIK interest notes to be issued		2,748			—			2,692			—
	Less: unamortized debt issue costs			(7,883	)		(962	)		(10,250	)		(1,168	)
															Face value of notes outstanding and notes to be issued	$	332,536		$	235,000		$	325,985		$	245,000
	Carrying value		$	326,314		$	234,038		$	322,286		$	233,832		Less: unamortized debt issue costs		(10,250	)		(1,168	)		(19,483	)		(2,077	)
															Carrying value	$	322,286		$	233,832		$	306,502		$	242,923
	Fair value of outstanding notes		$	339,681		$	165,894		$	335,295		$	151,928
															Fair value of outstanding notes	$	335,295		$	151,928		$	303,598		$	141,605

Secured_Note_Common_Stock_Warr2

Secured Note Common Stock Warrants	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Text Block [Abstract]	'	'
Secured Note Common Stock Warrants	'	'
	(12) Secured Note Common Stock Warrants	(13) Secured Note Common Stock Warrants
	On March 22, 2010, Alion issued 310,000 Units consisting of $1,000 of Secured Note face value and a warrant to purchase 1.9439 shares of Alion common stock. The Secured Note warrants entitle holders to purchase a total of 602,614 shares of Alion common stock. Each Secured Note warrant has an exercise price of a penny per share; the Secured Note warrants are not redeemable for cash.	On March 22, 2010, Alion issued 310,000 Units consisting of $1,000 of Secured Note face value and a warrant to purchase 1.9439 shares of Alion common stock. The Secured Note warrants entitle holders to purchase a total of 602,614 shares of Alion common stock. Each Secured Note warrant has an exercise price of a penny per share; the Secured Note warrants are not redeemable for cash.
	The Company registered the Secured Notes, but is not required to register the warrants. The Units separated into Secured Notes and warrants on June 22, 2010. Each warrant became exercisable on March 22, 2011 and expires on March 15, 2017.	The Company registered the Secured Notes, but is not required to register the warrants. The Units separated into Secured Notes and warrants on June 22, 2010. Each warrant became exercisable on March 22, 2011 and expires on March 15, 2017.
	The Secured Note warrants had an initial fair value of approximately $20.8 million based on Alion’s former share price of $34.50. Alion recognized the value of the warrants as part of the debt issue costs for the Secured Notes and recorded a corresponding credit to equity. The Company accounts for the Secured Note warrants as equity and reassesses this classification each reporting period. The Company identified no required changes in accounting treatment as of December 31, 2013.	The Secured Note warrants had an initial fair value of approximately $20.8 million based on Alion’s former share price of $34.50. Alion recognized the value of the warrants as part of the debt issue costs for the Secured Notes and recorded a corresponding credit to equity. The Company accounts for the Secured Note warrants as equity and reassesses this classification each reporting period. The Company identified no required changes in accounting treatment as of September 30, 2013.

Leases1

Leases	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Leases [Abstract]	'							'
Leases	'							'
	(13) Leases							(14) Leases
	Future minimum lease payments under non-cancelable operating leases for buildings, equipment and automobiles at December 31, 2013 are set out below. Alion subleases some excess capacity to subtenants under non-cancelable operating leases.							Future minimum lease payments under non-cancelable operating leases for buildings, equipment and automobiles at September 30, 2013 are set out below. Alion subleases some excess capacity to subtenants under non-cancelable operating leases.
	Lease Payments for Fiscal Years Ending	(In thousands)						Lease Payments for Fiscal Years Ending	(In thousands)
	2014 (for the remainder of fiscal year)	$	19,497					2014	$	26,009
	2015		25,076					2015		24,875
	2016		21,183					2016		21,041
	2017		17,783					2017		17,804
	2018		14,931					2018		14,931
	2019		6,162					And thereafter		19,109
	And thereafter		12,947
								Gross lease payments	$	123,769
	Gross lease payments	$	117,579					Less: non-cancelable subtenant receipts		(1,711	)
	Less: non-cancelable subtenant receipts		(1,593	)
								Net lease payments	$	122,058
	Net lease payments	$	115,986
	Composition of Total Rent Expense							Composition of Total Rent Expense
		Three Months Ended							September 30,
		December 31,							2013			2012			2011
		2013			2012				(In thousands)
		(In thousands)						Minimum rentals	$	21,530		$	20,639		$	21,992
	Minimum rentals	$	5,515		$	5,301		Less: Sublease rental income		(600	)		(156	)		(1,610	)
	Less: Sublease rental income		(143	)		(104	)
								Total rent expense, net	$	20,930		$	20,483		$	20,382
	Total rent expense, net	$	5,372		$	5,197

Postretirement_Benefits

Postretirement Benefits	12 Months Ended
	Sep. 30, 2013
Text Block [Abstract]	'
Postretirement Benefits	'
	(15) Postretirement Benefits
	Alion sponsors a postretirement plan providing medical, dental, and vision coverage to eligible former employees. The Company is self-insured with a stop-loss limit under an insurance agreement. The plan was closed to new participants in fiscal 2008. It provides benefits until age 65 for employees who met certain age and service requirements. Alion requires most participants to pay the full expected cost of benefits. A limited number of participants, eligible for coverage after age 65, contribute a lesser amount. As of September 30, 2013, the Company had recognized a $376 thousand unfunded plan liability. Alion paid $39 thousand, $59 thousand and $48 thousand in plan benefits for the years ended September 30, 2013, 2012, and 2011. Participants contributed $14 thousand, $12 thousand and $18 thousand for the years ended September 30, 2013, 2012, and 2011.

ESOP_Expense1

ESOP Expense	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'
ESOP Expense	'	'
	(14) ESOP Expense	(16) ESOP Expense
	Alion makes 401(k) matching contributions in shares of its common stock. The Company matches the first 3% and one-half of the next 2% of eligible employee salary deferrals by contributing shares of Alion common stock to the ESOP Trust on March 31 and September 30 each year. The Company also makes profit sharing contributions of Alion common stock to the ESOP Trust on the same dates.	Alion makes 401(k) matching and profit sharing contributions in shares of its redeemable common stock. The Company matches the first 3% and one-half of the next 2% of eligible employee salary deferrals by contributing shares of Alion common stock to the ESOP Trust on March 31 and September 30 each year. The Company also makes profit sharing contributions of 2.5% of eligible employee compensation by contributing shares of Alion common stock to the ESOP Trust on the same dates.
	Based on the value of common stock contributed and to be contributed to the Plan, Alion recognized $3.6 million and $3.4 million in Plan expense for the three months ended December 31, 2013 and 2012.	Formerly, through June 2011, Alion profit sharing contributions consisted of 1% of eligible employee compensation in common stock issued to the ESOP Trust and 1.5% of eligible employee compensation in cash to the 401(k) component. Alion recognized $13.8 million, $13.8 million and $13.2 million in Plan expense for the years ended September 30, 2013, 2012 and 2011. In 2011, Plan expense included approximately $1.2 million in cash and approximately $11.0 million in common stock.
	In September 2013, Alion amended the ESOP to permit Alion to delay the Company’s contribution to the Plan for the six months ended September 30, 2013 and to delay transfer to the Company of employee contributions for investment in the ESOP component of the Plan. The Company made its September 30 contribution on the same schedule as it has done in the past. In December 2013, the ESOP Trust used employee funds to purchase approximately $930 thousand of Alion common stock at the September 30, 2013 price of $8.10 per share.	In September 2013, Alion amended the ESOP to delay the Company’s contribution to the Plan for the six months ended September 30, 2013 and to delay transfer to the Company of employee contributions for investment in the ESOP component of the Plan. The Company made its September 30 contribution on the same schedule as it has done in the past. In December 2013, the ESOP Trust used employee funds to purchase approximately $930 thousand of Alion common stock at the September 30, 2013 price of $8.10 per share.
	The non-cash component of ESOP expense appears in the statement of cash flows supplemental disclosures as “common stock issued in satisfaction of employer contribution liability.” It is included in operating cash flows from changes in accrued liabilities.	The non-cash component of ESOP expense appears in the statement of cash flows supplemental disclosures as “common stock issued in satisfaction of employer contribution liability.” It is included in operating cash flows from changes in accrued liabilities. The Company issued $13.8 million in redeemable common stock for the year ended September 30, 2013.

Long_Term_Incentive_Plan

Long Term Incentive Plan	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Compensation Related Costs [Abstract]	'	'
Long Term Incentive Plan	'	'
	(15) Long Term Incentive Compensation Plan	(17) Long Term Incentive Plan
	Alion adopted a long-term cash incentive compensation plan for certain executives in December 2008. The Company amended its incentive compensation plan in January 2010 and amended and restated it in June 2013. The most recent amendment creates new change in control provisions that apply to future grants. Individual incentive compensation grants contain specific financial and performance goals and vest over varying periods. Some grants are for a fixed amount; others provide a range of values from a minimum of 50% to a maximum of 150% of initial grant value. The Company periodically evaluates the probability that individuals will achieve stated financial and performance goals.	Alion adopted a long-term cash incentive compensation plan for certain executives in December 2008. The Company amended its incentive compensation plan in January 2010 and amended and restated it in June 2013. The most recent amendment creates new change in control provisions that apply to future grants. Individual incentive compensation grants contain specific financial and performance goals and vest over varying periods. Some grants are for a fixed amount; others provide a range of values from a minimum of 50% to a maximum of 150% of initial grant value. The Company periodically evaluates the probability that individuals will achieve stated financial and performance goals.
	Alion recognizes long term incentive compensation expense based on outstanding grants’ stated values, estimated probability of achieving stated goals and estimated probable future grant values. The Company recognized $804 thousand and $742 thousand in incentive compensation expense for the quarters ended December 31, 2013 and 2012.	Alion recognizes long term incentive compensation expense based on outstanding grants’ stated values, estimated probability of achieving stated goals and estimated probable future grant values. The Company recognized $2.3 million, $1.4 million and $2.8 million in incentive compensation expense for the years ended September 30, 2013, 2012 and 2011.

Stockbased_Compensation

Stock-based Compensation	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Text Block [Abstract]	'	'
Stock-based Compensation	'	'
	(16) Stock Based Compensation	(18) Stock-based Compensation
	Alion initially adopted its Stock Appreciation Rights (SAR) Plan in 2004. The Company amended and restated the SAR Plan in January 2007; amended it in January 2010; and amended and restated the SAR Plan in June 2013. The SAR Plan expires in November 2016. The most recent SAR Plan amendment revises certain change in control provisions.	Alion initially adopted its Stock Appreciation Rights (SAR) Plan in 2004. The Company amended and restated the SAR Plan in January 2007; amended it in January 2010; and amended and restated the SAR Plan in June 2013. The SAR Plan expires in November 2016. The most recent SAR Plan amendment revises certain change in control provisions.
	The chief executive officer may award SARs as he deems appropriate. Awards vest ratably over four years with payment following the grant date fifth anniversary. Grants with no intrinsic value expire on their year-five payment date. The SAR Plan permits accelerated vesting in the event of death, disability or a change in control of the Company. Approximately 587 thousand SARs were outstanding at December 31, 2013, at a weighted average grant date fair value of $22.52 per share. No outstanding grant has any intrinsic value.	The chief executive officer may award SARs as he deems appropriate. Awards vest ratably over four years with payment following the grant date fifth anniversary. Grants with no intrinsic value expire on their year-five payment date. The SAR Plan provides for accelerated vesting in the event of death or disability and provides for accelerated vesting of existing grants on a change in control. Approximately 709 thousand SARs were outstanding at September 30, 2013, at a weighted average grant date fair value of $24.96 per share. No outstanding grant has any intrinsic value. For the years ended September 30, 2013, 2012 and 2011, Alion recognized credits of $219 thousand, $90 thousand and $146 thousand in stock-based compensation expense for the SAR Plan. The Company has an aggregate SAR Plan liability of $26 thousand.
	In June 2013, the Company amended and restated its Phantom Stock Plan and its Performance Shares and Retention Phantom Stock Plan. No grants are outstanding under either of these plans.	Phantom Stock Plans
	Alion recognized no stock-based compensation expense for the three months ended December 31, 2013 and $10 thousand in stock based compensation expense for the three months ended December 31, 2012.	Alion formerly maintained Executive and Director Phantom Stock Plans. In 2011, Alion paid out the final vested Director Plan grant and recognized compensation expense of $4 thousand. In June 2013, the Company amended and restated its Phantom Stock Plan and its Performance Shares and Retention Phantom Stock Plan. No grants are outstanding under either of these plans.
	The Company uses a Black-Scholes-Merton option pricing model based on the fair market value of a share of its common stock to recognize stock –based compensation expense. There is no established public trading market for Alion’s common stock. The ESOP Trust owns all outstanding common stock. Alion does not expect to pay any dividends on its common stock and intends to retain future earnings, if any, for operating its business.	The Company uses a Black-Scholes-Merton option pricing model based on the fair market value of a share of its common stock to recognize stock –based compensation expense. There is no established public trading market for Alion’s common stock. The ESOP Trust owns all outstanding common stock. Alion does not expect to pay any dividends on its common stock and intends to retain future earnings, if any, for operating its business.

Income_Taxes1

Income Taxes	3 Months Ended								12 Months Ended
	Dec. 31, 2013								Sep. 30, 2013
Income Tax Disclosure [Abstract]	'								'
Income Taxes	'								'
	-17	Income Taxes							(19) Income Taxes
	Deferred Taxes								Current Taxes
	Alion is subject to income taxes in the U.S., various states, India and Canada. Tax statutes and regulations within each jurisdiction are subject to interpretation requiring management to apply significant judgment. Alion recorded $1.7 million in goodwill-related deferred tax expense and liabilities for the three months ended December 31, 2013 and 2012. The Company recognized $2 thousand in current tax expense for its Indian subsidiary for the three months ended December 2013 and no current tax expense for the three months ended December 31, 2012.								Alion is subject to income taxes in the U.S., various states, Canada and India. Tax statutes and regulations within each jurisdiction are subject to interpretation requiring management to apply significant judgment. In 2013, the Company recognized approximately $2 thousand in current income tax expense for newly commenced business operations in India.
	The Company expects to be able to use existing and anticipated net operating losses (NOL) to offset taxes that may become due in the future if Alion has future taxable income. Even though Alion recorded a full valuation allowance for all deferred tax assets, the Company does not expect to pay any domestic income taxes for the foreseeable future and minimal foreign income taxes for its operations in India. Alion’s ability to utilize NOL tax benefits will depend upon how much future taxable income it has and may be limited under certain circumstances. Alion does not have any NOL tax benefits it can carry back to prior years.								Deferred Taxes
	The Company’s effective tax rate for the three months ended December 31, 2013 was -10.4% and -18.8% for the three months ended December 31, 2012. As of December 31, 2013 and September 30, 2013 the net deferred tax liability was:								Alion recorded approximately $7.0 million in deferred tax expense and liabilities related to tax-basis goodwill amortization in 2013, 2012 and 2011.
									Alion was formerly an S corporation and has been a C corporation since March 2010. The Company’s history of losses gives rise to a presumption that it might not be able to realize the full benefit of any deferred tax assets it is required to recognize. Therefore, Alion maintains a valuation allowance equal to the deferred tax assets it is required to recognize each reporting period and in total.
									The Company does not expect to pay any income taxes for the foreseeable future. Even though Alion has recorded a full valuation allowance for all deferred tax assets, management believes that if the Company were to become profitable, it should be able to use existing and anticipated net operating loss (NOL) carryforwards to offset taxes that might become due in the future. Alion’s ability to utilize NOL tax benefits will depend upon how much future taxable income it has and may be limited under certain circumstances. Alion does not have any NOL tax benefits it can carry back to years prior to becoming a C corporation.
			December 31,			September 30,
			2013			2013			The Company offers post-retirement prescription drug coverage to a limited number of retirees and beneficiaries. Alion has not claimed any federal tax credit in prior years. The Affordable Care Act has reduced the value of the federal subsidy for retiree drug coverage. Alion’s tax provision is unaffected by this legislative change. Management will decide whether to seek a subsidy in the future based on its anticipated value and the cost associated with seeking the subsidy.
			(In thousands)						Tax Uncertainties
	Current deferred tax asset		$	7,355		$	9,228		FASB Interpretation No. 48, “Accounting for Uncertainty in Income Taxes” now codified as ASC Topic 740 Income Taxes prescribes a recognition threshold and a measurement attribute for financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. The Company may recognize a benefit for that amount which it has a more than 50% chance of realizing. If the Company’s position involves uncertainty, then in order to recognize a benefit, a given tax position must be “more-likely-than-not” to be sustained upon examination by taxing authorities.
	Noncurrent deferred tax asset			98,007			87,812		Alion periodically assesses its liabilities and contingencies for all periods open to examination by tax authorities, based on the latest available information. Where management believes there is more than a 50 percent chance the Company’s tax position will not be sustained, Alion records its best estimate of the resulting tax liability, including interest. Interest or penalties related to income taxes are reported separately from income tax expense. The Company has analyzed its tax positions and has not recorded any liabilities for tax uncertainties.
	Valuation allowance			(105,362	)		(97,040	)	The Company has unrecorded tax benefits related to goodwill deductions. If Alion is able to utilize these benefits to reduce taxes payable in the future, it will recognize a reduction in its income tax liability and a corresponding reduction in goodwill carrying value.
	Noncurrent deferred tax liability			(59,873	)		(58,130	)	Alion may become subject to federal or state income tax examination for tax years ended September 2010 and after. Each of the Company’s open return year returns has given rise to an NOL carryforward including the Company’s 2010 return in which it elected not to defer the gain recognized on extinguishing certain former debt instruments. The Company does not expect resolution of tax matters for any open years to materially affect operating results, financial condition, cash flows or its effective tax rate.
									As of September 30, 2013 and 2012 deferred tax assets and related valuation allowances were $97.0 million and $78.4 million and deferred tax liabilities were $58.1 million and $51.2 million. Alion’s effective tax rate for fiscal years 2013, 2012 and 2011 was (23.6%), (20.2%) and (18.6%).
	Net deferred tax liability		$	(59,873	)	$	(58,130	)	The provision for income taxes for the years ended September 30, 2013, 2012 and 2011 was:
	Tax Uncertainties
	Based on the latest available information, Alion periodically assesses its liabilities and contingencies for all periods open to examination by tax authorities. Where management believes there is more than a 50 percent chance the Company’s tax position will not be sustained, Alion records its best estimate of the resulting tax liability, including interest. Interest or penalties related to income taxes are reported separately from income tax expense. The Company has analyzed its tax positions and has not recorded any liabilities for tax uncertainties.									Fiscal Years Ended
										September 30,
	Alion may become subject to federal or state income tax examination for tax years ended September 2010 and after. Alion’s former status as a pass-through entity owned by a tax-exempt trust makes an examination unlikely and the possibility of an adverse determination remote. The Company does not expect resolution of tax matters for any open years to materially affect its operating results, financial condition, cash flows or effective tax rate.									2013			2012			2011
										(In thousands)
									Current:
									Foreign		3			—			—
									Total current provision	$	3			—		$	—
									Deferred:
									Federal	$	5,740			5,740		$	5,740
									State		1,234			1,234			1,234
									Total deferred provision	$	6,974			6,974		$	6,974
									Total provision for income taxes	$	6,977			6,974		$	6,974
									Alion’s income tax provisions at September 30, 2013, 2012 and 2011 include the effects of state income taxes, debt extinguishment and changes in valuation allowances. The provision for income taxes for the years ended September 30, 2013, 2012 and 2011 differ from the amounts computed by applying the statutory U.S. federal income tax rate to income before taxes as a result of the following:
										Fiscal Years Ended September 30,
										2013						2012						2011
										(Dollars in thousands)
									Expected federal income tax (benefit)		35	%	$	(10,365	)		35	%	$	(12,066	)		35	%	$	(13,093	)
									State income taxes (net of federal benefit)		4.5	%		(1,325	)		4.5	%		(1,539	)		4.5	%		(1,666	)
									Nondeductible expenses		(0.4	%)		105			(0.4	%)		146			(0.6	%)		232
									Provision to return true-ups		(0.1	%)		15			(0.8	%)		286			(0.2	%)		84
									Tax credits		0.3	%		(79	)		0	%		—			0	%		—
									Changes in valuation allowance		(62.9	%)		18,626			(58.4	%)		20,147			(57.2	%)		21,417
									Income tax expense (benefit)		(23.6	%)	$	6,977			(20.2	%)	$	6,974			(18.6	%)	$	6,974
									At September 30, 2013 and 2012, the components of deferred tax assets and deferred tax liabilities were:
										September 30,
										2013			2012
										(In thousands)
									Deferred tax assets:
									Accrued expenses and reserves	$	9,228		$	11,206
									Intangible amortization		13,185			14,305
									Deferred rent		3,680			3,398
									Deferred wages		4,060			3,954
									Depreciation and leases		4,375			3,226
									Carryforwards and tax credits		62,487			42,300
									Other		25			25
									Gross deferred tax assets	$	97,040		$	78,414
									Less Valuation		(97,040	)		(78,414	)
									Deferred tax liabilities:
									Goodwill		(58,130	)		(51,156	)
									Net deferred tax asset/(liability)	$	(58,130	)	$	(51,156	)

Segment_Information_and_Custom

Segment Information and Customer Concentration	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Segment Reporting [Abstract]	'	'
Segment Information and Customer Concentration	'	'
	(18) Segment Information	(20) Segment Information and Customer Concentration
	Alion operates as a single segment, providing advanced engineering, information technology and operational solutions to strengthen national security and drive business results under contracts with the U.S. government, state and local governments, and commercial customers.	Alion operates as a single segment, providing advanced engineering, information technology and operational solutions to strengthen national security and drive business results under contracts with the U.S. government, state and local governments, and commercial customers.
	U.S. government customers typically exercise independent contracting authority. U.S. government agencies, department offices or divisions may use Alion’s services as a separate customer directly, or through a prime contractor, if they have independent decision-making and contracting authority within their organization. U.S. government prime contracts accounted for approximately 87% and 89% of total contract revenue for the three months ended December 31, 2013, and 2012.	U.S. government customers typically exercise independent contracting authority. U.S. government agencies, department offices or divisions may use Alion’s services as a separate customer directly, or through a prime contractor, if they have independent decision-making and contracting authority within their organization. U.S. government prime contracts accounted for approximately 89%, 86%, and 84% of total contract revenue for the years ended September 30, 2013, 2012 and 2011. The following five prime contracts represented over 50% of our revenue for the past three years.
				Fiscal Years Ended
				September 30,
		Government Agency	Contract	2013			2012			2011
		DoD—Defense Information Systems Agency	Weapons System Information Analysis Center for the Defense Information Systems Agency (ID/IQ contract vehicle)		27.6	%		17.1	%		8.2	%
		DoD—U.S. Navy	Seaport-E Multiple Award Contract for the Naval Sea Systems Command (ID/IQ contract vehicle)		20.7	%		20.1	%		13.5	%
		DoD—U.S. Air Force	Technical and Analytical Support for the U.S. Air Force		8.4	%		9.9	%		11.2	%
		DoD—U.S. Navy	Naval Sea Systems Command Surface Ships Life Cycle Program Management and Engineering Support		7.2	%		5.8	%		N/A
		DoD—Defense Information Systems Agency	Modeling and Simulation Information Analysis Center for the Defense Information Systems Agency (ID/IQ contract vehicle)		2.5	%		8.1	%		14.1	%

GuarantorNonguarantor_Condense

Guarantor/Non-guarantor Condensed Consolidated Financial Information	3 Months Ended																	12 Months Ended
	Dec. 31, 2013																	Sep. 30, 2013
Text Block [Abstract]	'																	'
Guarantor/Non-guarantor Condensed Consolidated Financial Information	'																	'
	-20	Guarantor/Non-guarantor Unaudited Condensed Consolidated Financial Information																(21) Guarantor/Non-guarantor Condensed Consolidated Financial Information
	Certain of Alion’s 100% owned domestic subsidiaries have jointly, severally, fully and unconditionally guaranteed both the Secured Notes and the Unsecured Notes which are general obligations of the Company. In March 2010, the Unsecured Note Indenture was amended to include as Unsecured Note guarantors all subsidiaries serving as Secured Note guarantors.																	Certain of Alion’s 100% owned domestic subsidiaries have jointly, severally, fully and unconditionally guaranteed both the Secured Notes and the Unsecured Notes which are general obligations of the Company. In March 2010, the Unsecured Note Indenture was amended to include as Unsecured Note guarantors all subsidiaries serving as Secured Note guarantors.
	The following information presents unaudited condensed consolidating balance sheets as of December 31, 2013 and September 30, 2013; unaudited condensed consolidating statements of operations and comprehensive loss for the three month period ended December 31, 2013 and 2012; and unaudited condensed consolidating statements of cash flows for the three months ended December 31, 2013 and 2012 of Alion, its guarantor subsidiaries and its non-guarantor subsidiaries. Investments include Alion’s investments in its subsidiaries presented using the equity method of accounting.																	The following information presents condensed consolidating balance sheets as of September 30, 2013 and September 30, 2012; condensed consolidating statements of operations and comprehensive loss and cash flows for the years ended September 30, 2013, 2012 and 2011 of Alion, its guarantor subsidiaries and its non-guarantor subsidiaries. Investments include Alion’s investments in its subsidiaries presented using the equity method of accounting.
	Condensed Consolidating Balance Sheet as of December 31, 2013 (unaudited)																	Condensed Consolidating Balance Sheet Information at September 30, 2013
			Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
						Companies			Guarantor													Companies			Companies
									Companies										(In thousands)
			(In thousands)															Current assets:
	Current assets:																	Cash and cash equivalents	$	25,617		$	(24	)	$	20		$	—		$	25,613
	Cash and cash equivalents		$	4,670		$	(10	)	$	27		$	—		$	4,687		Accounts receivable, net		169,304			2,735			565			—			172,604
	Accounts receivable, net			166,283			2,038			642			—			168,963		Receivable due from ESOP Trust		930			—			—			—			930
	Prepaid expenses and other current assets			5,587			36			25			—			5,648		Prepaid expenses and other current assets		4,449			188			(154	)		—			4,483
	Total current assets			176,540			2,064			694			—			179,298		Total current assets		200,300			2,899			431			—			203,630
	Property, plant and equipment, net			8,552			515			3			—			9,070		Property, plant and equipment, net		9,139			525			4			—			9,668
	Intangible assets, net			1,735			—			—			—			1,735		Intangible assets, net		2,040			—			—			—			2,040
	Goodwill			398,921			—			—			—			398,921		Goodwill		398,921			—			—			—			398,921
	Investment in subsidiaries			28,710			—			—			(28,710	)		—		Investment in subsidiaries		28,420			—			—			(28,420	)		—
	Intercompany receivables			1,963			28,536			—			(30,499	)		—		Intercompany receivables		1,906			27,828			—			(29,734	)		—
	Other assets			10,364			—			4			—			10,368		Other assets		10,363			—			4			—			10,367
	Total assets		$	626,785		$	31,115		$	701		$	(59,209	)	$	599,392		Total assets	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
	Current liabilities:																	Current liabilities:
	Interest payable		$	15,590		$	—		$	—		$	—		$	15,590		Interest payable	$	17,758		$	—		$	—		$	—		$	17,758
	Secured notes			326,313			—			—			—			326,313		Trade accounts payable		61,563			58			1			—			61,622
	Trade accounts payable			59,465			40			31			—			59,536		Accrued liabilities		39,169			144			80			—			39,393
	Accrued liabilities			36,710			96			103			—			36,909		Accrued payroll and related liabilities		37,404			517			33			—			37,954
	Accrued payroll and related liabilities			31,399			303			31			—			31,733		Billings in excess of costs revenue earned		4,250			84			—			—			4,334
	Billings in excess of revenue earned			4,452			110			—			—			4,562
																		Total current liabilities		160,144			803			114			—			161,061
	Total current liabilities			473,929			549			165			—			474,643		Intercompany payables		27,826			153			1,754			(29,733	)		—
	Intercompany payables			28,537			—			1,962			(30,499	)		—		Secured Notes		322,286			—			—			—			322,286
	Unsecured notes			234,038			—			—			—			234,038		Unsecured Notes		233,832			—			—			—			233,832
	Accrued compensation and benefits, excluding current portion			5,998			—			—			—			5,998		Accrued compensation and benefits, excluding current portion		5,736			—			—			—			5,736
	Non-current portion of lease obligations			12,110			430			—			—			12,540		Non-current portion of lease obligations		12,374			447			—			—			12,821
	Deferred income taxes			59,873			—			—			—			59,873		Deferred income taxes		58,130			—			—			—			58,130
	Commitments and contingencies																	Commitments and contingencies		—			—			—			—			—
	Redeemable common stock			61,896			—			—			—			61,896		Redeemable common stock		61,895			—			—			—			61,895
	Common stock warrants			20,785			—			—			—			20,785		Common stock warrants		20,785			—			—			—			20,785
	Common stock of subsidiaries			—			4,084			9			(4,093	)		—		Common stock of subsidiaries		—			4,084			9			(4,093	)		—
	Accumulated other comprehensive loss			130			—			—			—			130		Accumulated other comprehensive loss		130			—			—			—			130
	Accumulated deficit			(270,511	)		26,052			(1,435	)		(24,617	)		(270,511	)	Accumulated surplus (deficit)		(252,049	)		25,765			(1,438	)		(24,328	)		(252,050	)
	Total liabilities, redeemable common stock and accumulated deficit		$	626,785		$	31,115		$	701		$	(59,209	)	$	599,392		Total liabilities, redeemable common stock and stockholder’s deficit	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
	Condensed Consolidating Balance Sheet as of September 30, 2013 (unaudited)																	Condensed Consolidating Balance Sheet Information at September 30, 2012
			Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
									Guarantor													Companies			Companies
									Companies										(In thousands)
			(In thousands)															Current assets:
	Current assets:																	Cash and cash equivalents	$	27,271		$	(44	)	$	—		$	—		$	27,227
	Cash and cash equivalents		$	25,617		$	(24	)	$	20		$	—		$	25,613		Accounts receivable, net		172,365			2,783			145			—			175,293
	Accounts receivable, net			169,304			2,735			565			—			172,604		Receivable due from ESOP Trust		1,129			—			—			—			1,129
	Receivable due from ESOP Trust			930			—			—			—			930		Prepaid expenses and other current assets		5,378			70			—			—			5,448
	Prepaid expenses and other current assets			4,449			188			(154	)		—			4,483
																		Total current assets		206,143			2,809			145			—			209,097
	Total current assets			200,300			2,899			431			—			203,630		Property, plant and equipment, net		10,064			529			12			—			10,605
	Property, plant and equipment, net			9,139			525			4			—			9,668		Intangible assets, net		5,242			—			—			—			5,242
	Intangible assets, net			2,040			—			—			—			2,040		Goodwill		398,921			—			—			—			398,921
	Goodwill			398,921			—			—			—			398,921		Investment in subsidiaries		27,994			—			—			(27,994	)		—
	Investment in subsidiaries			28,420			—			—			(28,420	)		—		Intercompany receivables		1,438			27,475			—			(28,913	)		—
	Intercompany receivables			1,906			27,828			—			(29,734	)		—		Other assets		11,427			—			4			—			11,431
	Other assets			10,363			—			4			—			10,367
																		Total assets	$	661,229		$	30,813		$	161		$	(56,907	)	$	635,296
	Total assets		$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
																		Current liabilities:
	Current liabilities:																	Interest payable	$	17,658		$	—		$	—		$	—		$	17,658
Interest payable		$	17,758		$	—		$	—		$	—		$	17,758		Trade accounts payable		44,582			201			10			—			44,793
Trade accounts payable			61,563			58			1			—			61,622		Accrued liabilities		52,265			190			5			—			52,460
Accrued liabilities			39,169			144			80			—			39,393		Accrued payroll and related liabilities		39,305			589			32			—			39,926
Accrued payroll and related liabilities			37,404			517			33			—			37,954		Billings in excess of costs revenue earned		2,656			6			4			—			2,666
Billings in excess of costs revenue earned			4,250			84			—			—			4,334
																	Total current liabilities		156,466			986			51			—			157,503
Total current liabilities			160,144			803			114			—			161,061		Intercompany payables		27,476			—			1,437			(28,913	)		—
Intercompany payables			27,826			153			1,754			(29,733	)		—		Secured Notes		306,502			—			—			—			306,502
Secured Notes			322,286			—			—			—			322,286		Unsecured Notes		242,923			—			—			—			242,923
Unsecured Notes			233,832			—			—			—			233,832		Accrued compensation and benefits, excluding current portion		5,905			—			—			—			5,905
Accrued compensation and benefits, excluding current portion			5,736			—			—			—			5,736		Non-current portion of lease obligations		11,858			506			—			—			12,364
Non-current portion of lease obligations			12,374			447			—			—			12,821		Deferred income taxes		51,156			—			—			—			51,156
Deferred income taxes			58,130			—			—			—			58,130		Commitments and contingencies
Redeemable common stock			61,895			—			—			—			61,895		Redeemable common stock		110,740			—			—			—			110,740
Common stock of subsidiaries			—			4,084			9			(4,093	)		—		Common stock warrants		20,785			—			—			—			20,785
Commitments and contingencies																	Common stock of subsidiaries		—			4,084			—			(4,084	)		—
Common stock warrants			20,785			—			—			—			20,785		Accumulated other comprehensive loss		(149	)		—			—			—			(149	)
Accumulated other comprehensive loss			130			—			—			—			130		Accumulated surplus (deficit)		(272,433	)		25,237			(1,327	)		(23,910	)		(272,433	)
Accumulated surplus (deficit)			(252,049	)		25,765			(1,438	)		(24,328	)		(252,050	)
																	Total liabilities, redeemable common stock and stockholder’s deficit	$	661,229		$	30,813		$	161		$	(56,907	)	$	635,296
Total liabilities, redeemable common stock and accumulated deficit		$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
																	Condensed Consolidating Statement of Comprehensive Loss
Condensed Consolidating Statement of Operations and Comprehensive Loss for the Three Months Ended December 31, 2013 (unaudited)
																		Year Ended September 30, 2013
		Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
					Companies			Guarantor													Companies			Companies
								Companies										(In thousands)
		(In thousands)															Contract revenue	$	839,608		$	8,627		$	737		$	—		$	848,972
Contract revenue		$	183,384			1,771			225			—		$	185,380		Direct contract expenses		663,380			5,638			486			—			669,504
Direct contract expense			144,060			1,091			124			—			145,275
																	Gross profit		176,228			2,989			251			—			179,468
Gross profit			39,324			680			101			—			40,105
																	Operating expenses		81,838			1,972			318			—			84,128
Operating expenses			18,385			392			87						18,864		General and administrative		52,491			604			44			—			53,139
General and administrative			18,983			1			9			—			18,993
																	Operating income (loss)		41,899			413			(111	)		—			42,201
Operating income			1,956			287			5			—			2,248		Other income (expense):
Other income (expense):																	Interest income		55			—			—			—			55
Interest income			11			—			—			—			11		Interest expense		(75,700	)		—			—			—			(75,700	)
Interest expense			(18,948	)		—			—			—			(18,948	)	Other		(200	)		116			—			—			(84	)
Other			(28	)					—			—			(28	)	Gain on debt extinguishment		3,913			—			—			—			3,913
Equity in net income (loss) of subsidiaries			292						—			(292	)		—		Equity in net income (loss) of subsidiaries		418			—			—			(418	)		—
Total other expenses			(18,673	)		—			—			(292	)		(18,965	)	Total other income (expense)		(71,514	)		116			—			(418	)		(71,816	)
																	Income (loss) before taxes		(29,615	)		529			(111	)		(418	)		(29,615	)
(Loss) income before taxes			(16,717	)		287			5			(292	)		(16,717	)	Income tax expense		(6,977	)		—			—			—			(6,977	)
Income tax expense			(1,745	)		—			—			—			(1,745	)
																	Net income (loss)	$	(36,592	)	$	529		$	(111	)	$	(418	)	$	(36,592	)
Net loss		$	(18,462	)	$	287		$	5		$	(292	)	$	(18,462	)
																	Other comprehensive income:
Other comprehensive income																	Postretirement actuarial gains		279			—			—			—			279
Postretirement actuarial gains			—			—			—			—			—
																	Comprehensive income (loss)	$	(36,313	)		529			(111	)		(418	)		(36,313	)
Comprehensive income (loss)		$	(18,462	)	$	287		$	5		$	(292	)	$	(18,462	)
																	Condensed Consolidating Statement of Comprehensive Loss
Condensed Consolidating Statement of Operations and Comprehensive Loss for the Three Months Ended December 31, 2012 (unaudited)
																		Year Ended September 30, 2012
																		Parent			Guarantor			Non-			Eliminations			Consolidated
		Parent			Guarantor			Non-			Eliminations			Consolidated							Companies			Guarantor
					Companies			Guarantor																Companies
								Companies										(In thousands)
		(In thousands)															Contract revenue	$	802,664		$	14,015		$	525		$	—		$	817,204
Contract revenue		$	202,057		$	2,218		$	54		$	—		$	204,329		Direct contract expenses		624,788			7,743			300			—			632,831
Direct contract expense			159,162			1,337			136			—			160,635
																	Gross profit		177,876			6,272			225			—			184,373
Gross profit			42,895			881			(82	)		—			43,694
																	Operating expenses		88,736			2,531			227			—			91,494
Operating expenses			21,621			560			69			—			22,250		General and administrative		52,123			156			162			—			52,441
General and administrative			11,734			49			21			—			11,804
																	Operating income (loss)		37,017			3,585			(164	)		—			40,438
Operating income (loss)			9,540			272			(172	)		—			9,640		Other income (expense):
Other income (expense):																	Interest income		78			—			—			—			78
Interest income			17			—			—			—			17		Interest expense		(74,934	)		—			—			—			(74,934	)
Interest expense			(18,919	)		—			—			—			(18,919	)	Other		(63	)		9			(1	)		—			(55	)
Other			(15	)		—			—			—			(15	)	Equity in net income (loss) of subsidiaries		3,429			—			—			(3,429	)		—
Equity in net income of subsidiaries			100			—			—			(100	)		—
																	Total other income (expense)		(71,490	)		9			(1	)		(3,429	)		(74,911	)
Total other (expense) income			(18,817	)		—			—			(100	)		(18,917	)	Income (loss) before taxes		(34,473	)		3,594			(165	)		(3,429	)		(34,473	)
																	Income tax expense		(6,974	)		—			—			—			(6,974	)
(Loss) income before taxes			(9,277	)		272			(172	)		(100	)		(9,277	)
Income tax expense			(1,744	)		—			—			—			(1,744	)	Net income (loss)	$	(41,447	)	$	3,594		$	(165	)	$	(3,429	)	$	(41,447	)
Net income (loss)		$	(11,021	)	$	272		$	(172	)	$	(100	)	$	(11,021	)	Other comprehensive income:
																	Postretirement actuarial gains		26			—			—			—			26
Other comprehensive income:
Postretirement actuarial gains			—			—			—			—			—		Comprehensive income (loss)	$	(41,421	)		3,594			(165	)		(3,429	)		(41,421	)
Comprehensive income (loss)		$	(11,021	)	$	272		$	(172	)	$	(100	)	$	(11,021	)	Condensed Consolidating Statement of Comprehensive Loss
Condensed Consolidating Statement of Cash Flows for the Three Months Ended December 31, 2013 (unaudited)																		Year Ended September 30, 2011
																		Parent			Guarantor			Non-			Eliminations			Consolidated
																					Companies			Guarantor
		Parent			Guarantor			Non-			Consolidated													Companies
					Companies			Guarantor										(In thousands)
								Companies									Contract revenue	$	769,467		$	17,025		$	822		$	—		$	787,314
		(In thousands)															Direct contract expenses		593,600			9,333			548			—			603,481
Net cash (used in) provided by operating activities		$	(19,934	)	$	24		$	7		$	(19,903	)
																	Gross profit		175,867			7,692			274			—			183,833
Cash flows from investing activities:
Capital expenditures			(263	)		(10	)		—			(273	)				Operating expenses		79,871			3,076			88			—			83,035
																	General and administrative		64,374			620			311			—			65,305
Net cash used in investing activities			(263	)		(10	)		—			(273	)
Cash flows from financing activities:																	Operating income (loss)		31,622			3,996			(125	)		—			35,493
Payment of debt issue costs			(750	)		—			—			(750	)				Other income (expense):
Revolver borrowings			10,000			—			—			10,000					Interest income		45			—			—			—			45
Revolver payments			(10,000	)		—			—			(10,000	)				Interest expense		(73,919	)		—			—			—			(73,919	)
Redeemable common stock purchased from ESOP Trust			(934	)		—			—			(934	)				Other		(535	)		568			(1	)		—			32
Redeemable common stock sold to ESOP Trust			934			—			—			934					Gain on debt extinguishment		939			—			—			—			939
																	Equity in net income (loss) of subsidiaries		4,438			—			—			(4,438	)		—
Net cash used in financing activities			(750	)		—			—			(750	)
Net (decrease) increase in cash and cash equivalents			(20,947	)		14			7			(20,926	)				Total other income (expense)		(69,032	)		568			(1	)		(4,438	)		(72,903	)
Cash and cash equivalents at beginning of period			25,617			(24	)		20			25,613					Income (loss) before taxes		(37,410	)		4,564			(126	)		(4,438	)		(37,410	)
																	Income tax expense		(6,974	)		—			—			—			(6,974	)
Cash and cash equivalents at end of period		$	4,670		$	(10	)	$	27		$	4,687
																	Net income (loss)	$	(44,384	)	$	4,564		$	(126	)	$	(4,438	)	$	(44,384	)
Condensed Consolidating Statement of Cash Flows for the Three Months Ended December 31, 2012 (unaudited)																	Other comprehensive income:
																	Post retirement actuarial gains		55			—			—			—			55
		Parent			Guarantor			Non-			Consolidated						Comprehensive income (loss)		(44,329	)		4,564			(126	)		(4,438	)		(44,329	)
					Companies			Guarantor
								Companies									Condensed Consolidating Statement of Cash Flows
		(In thousands)															Year Ended September 30, 2013
Net cash (used in) provided by operating activities		$	(6,337	)	$	15		$	5		$	(6,317	)
Cash flows from investing activities:																		Parent			Guarantors			Non-			Consolidated
Capital expenditures			(603	)		—			—			(603	)											Guarantors
																		(In thousands)
Net cash used in investing activities			(603	)		—			—			(603	)				Net cash provided by operating activities	$	10,666		$	97		$	20		$	10,783
Cash flows from financing activities:																	Cash flows from investing activities:
Redeemable common stock purchased from ESOP Trust			(1,975	)		—			—			(1,975	)				Capital expenditures		(1,792	)		(77	)		—			(1,869	)
Net cash provided by financing activities			(846	)		—			—			(846	)				Net cash provided by (used in) investing activities		(1,792	)		(77	)		—			(1,869	)
Net increase (decrease) in cash and cash equivalents			(7,786	)		15			5			(7,766	)				Cash flows from financing activities:
Cash and cash equivalents at beginning of period			27,271			(44	)		—			27,227					Repurchase of Unsecured Notes		(6,030	)		—			—			(6,030	)
																	Revolver borrowings		16,461			—			—			16,461
Cash and cash equivalents at end of period		$	19,485		$	(29	)	$	5		$	19,461					Revolver repayments		(16,461	)		—			—			(16,461	)
																	Loan to ESOP Trust		(1,907	)		—			—			(1,907	)
																	ESOP loan repayment		1,907			—			—			1,907
																	Redeemable common stock purchased from ESOP Trust		(6,664	)		—			—			(6,664	)
																	Redeemable common stock sold to ESOP Trust		2,166			—			—			2,166
																	Net cash used in financing activities		(10,528	)		—			—			(10,528	)
																	Net increase (decrease) in cash and cash equivalents		(1,654	)		20			20			(1,614	)
																	Cash and cash equivalents at beginning of period		27,271			(44	)		—			27,227
																	Cash and cash equivalents at end of period	$	25,617		$	(24	)	$	20		$	25,613
																	Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2012
																		Parent			Guarantors			Non-			Consolidated
																								Guarantors
																		(In thousands)
																	Net cash provided by (used in) operating activities	$	12,700		$	(19	)	$	—		$	12,681
																	Cash flows from investing activities:
																	Capital expenditures		(2,733	)		2			—			(2,731	)
																	Net cash provided by (used in) investing activities		(2,733	)		2			—			(2,731	)
																	Cash flows from financing activities:
																	Revolver borrowings		26,000			—			—			26,000
																	Revolver repayments		(26,000	)		—			—			(26,000	)
																	Loan to ESOP Trust		(477	)		—			—			(477	)
																	ESOP loan repayment		477			—			—			477
																	Redeemable common stock purchased from ESOP Trust		(4,843	)		—			—			(4,843	)
																	Redeemable common stock sold to ESOP Trust		1,302			—			—			1,302
																	Net cash used in financing activities		(3,541	)		—			—			(3,541	)
																	Net increase (decrease) in cash and cash equivalents		6,426			(17	)		—			6,409
																	Cash and cash equivalents at beginning of period		20,845			(27	)		—			20,818
																	Cash and cash equivalents at end of period	$	27,271		$	(44	)	$	—		$	27,227
																	Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2011
																		Parent			Guarantors			Non-			Consolidated
																								Guarantors
																		(In thousands)
																	Net cash provided by operating activities	$	5,061		$	636		$	24		$	5,721
																	Cash flows from investing activities:
																	Capital expenditures		(5,694	)		(588	)		(23	)		(6,305	)
																	Proceeds from sale of fixed assets		14			—			—			14
																	Net cash used in investing activities		(5,680	)		(588	)		(23	)		(6,291	)
																	Cash flows from financing activities:
																	Payment of debt issuance cost		(710	)		—			—			(710	)
																	Repurchase unsecured notes		(3,993	)		—			—			(3,993	)
																	Revolver borrowings		17,000			—			—			17,000
																	Revolver payments		(17,000	)		—			—			(17,000	)
																	Loan to ESOP Trust		(776	)		—			—			(776	)
																	ESOP loan repayment		776			—			—			776
																	Redeemable common stock purchased from ESOP Trust		(5,762	)		—			—			(5,762	)
																	Redeemable common stock sold to ESOP Trust		5,158			—			—			5,158
																	Net cash used in financing activities		(5,307	)		—			—			(5,307	)
																	Net increase (decrease) in cash and cash equivalents		(5,926	)		48			1			(5,877	)
																	Cash and cash equivalents at beginning of period		26,770			(74	)		(1	)		26,695
																	Cash and cash equivalents at end of period	$	20,844		$	(26	)	$	—		$	20,818

Commitments_and_Contingencies1

Commitments and Contingencies	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'		'
Commitments and Contingencies	'		'
	-19	Commitments and Contingencies	(22) Commitments and Contingencies
	Government Audits		Government Audits
	Federal government cost-reimbursement contract revenues and expenses in the unaudited condensed consolidated financial statements are subject to DCAA audit and possible adjustment. Alion is a major contractor and DCAA maintains an office on site to perform various audits throughout the year. The Company has settled indirect rates through 2005 based on completed DCAA audits. All subsequent years are open. We are disputing the government’s claim for penalties and interest for 2005. It is our position that the statute of limitations has expired on any government contractual claims, including any claims for penalties and interest, on our 2005 indirect rate proposal. Alion has recorded federal government contract revenue based on amounts it expects to realize upon final settlement.		Federal government cost-reimbursement contract revenues and expenses in the audited consolidated financial statements are subject to DCAA audit and possible adjustment. Alion is a major contractor and DCAA maintains an office on site to perform various audits throughout the year. The Company has settled indirect rates through 2005 based on completed DCAA audits. All subsequent years are open. Alion has recorded federal government contract revenue based on amounts it expects to realize upon final settlement.
	Legal Proceedings		Legal Proceedings
	We are involved in routine legal proceedings occurring in the ordinary course of business that we believe are not material to our financial condition, operating results, or cash flows. As a government contractor, from time to time we may be subject to DCAA audits and federal government inquiries. The federal government may suspend or debar for a period of time any federal contractor it finds has violated the False Claims Act, and any contractor indicted or convicted of violations of other federal laws. The federal government could also impose fines or penalties.		We are involved in routine legal proceedings occurring in the ordinary course of business that we believe are not material to our financial condition, operating results, or cash flows. As a government contractor, from time to time we may be subject to DCAA audits and federal government inquiries. The federal government may suspend or debar for a period of time any federal contractor it finds has violated the False Claims Act, and any contractor indicted or convicted of violations of other federal laws. The federal government could also impose fines or penalties.
	Alion depends on federal government contracts; suspension or debarment could have a material, adverse effect on our business, financial condition, operating results, cash flows and our ability to meet our financial obligations. We are not aware of any such pending federal government claims or investigations.		Alion depends on federal government contracts; suspension or debarment could have a material, adverse effect on our business, financial condition, operating results, cash flows and our ability to meet our financial obligations. We are not aware of any such pending federal government claims or investigations.

Interim_Period

Interim Period	12 Months Ended
	Sep. 30, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Interim Period	'
	(23) Interim Period (Unaudited, in thousands except per share information)
		2013 Quarters
		1st			2nd			3rd			4th
	Revenue	$	204,329		$	221,281		$	220,947		$	202,415
	Gross profit	$	43,694		$	46,319		$	46,633		$	42,822
	Net loss	$	(11,021	)	$	(9,131	)	$	(7,087	)	$	(9,353	)
	Net loss per share	$	(1.64	)	$	(1.39	)	$	(1.01	)	$	(1.37	)
	Current assets	$	203,722		$	223,550		$	211,464		$	203,630
	Current liabilities	$	157,168		$	171,700		$	167,253		$	161,061
		2012 Quarters
		1st			2nd			3rd			4th
	Revenue	$	189,891		$	197,112		$	211,514		$	218,687
	Gross profit	$	43,547		$	46,681		$	46,472		$	47,673
	Net loss	$	(12,810	)	$	(10,245	)	$	(8,866	)	$	(9,526	)
	Net loss per share	$	(2.12	)	$	(1.73	)	$	(1.39	)	$	(1.52	)
	Current assets	$	205,819		$	200,703		$	211,266		$	209,097
	Current liabilities	$	166,226		$	152,200		$	166,520		$	157,503

Subsequent_Event1

Subsequent Event	3 Months Ended		12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013
Subsequent Events [Abstract]	'		'
Subsequent Event	'		'
	-21	Subsequent Event	(24) Subsequent Events
	In January 2014, the Board of Directors authorized the Company to file a registration statement on Form S-1 with the U.S. Securities and Exchange Commission to register the offer to exchange Unsecured Notes for, at the holders’ option, either (a) new third lien notes of equivalent face value, with a combination of interest payable in cash and in kind, and new warrants to purchase up to 27.5% of the Company’s common stock or (b) a limited amount of cash at a price below par plus accrued and unpaid interest and a 1.5% early tender cash payment, if applicable. The registration statement also registers the offer of new third lien notes and warrants to holders of Unsecured Notes who tender their Unsecured Notes in the exchange offer and meet certain other conditions.		Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of a potential covenant breach, resulting from an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this covenant. The Company paid no fee for this waiver.
			Also in December 2013, the Company sold approximately $934 thousand worth of its common stock to the ESOP Trust. The Company offered and sold the securities to the ESOP Trust pursuant to an exemption from registration under Section 4(2) of the Securities Act of 1933, as amended.

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Policies)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Accounting Policies [Abstract]	'	'
Basis Of Presentation And Principles Of Consolidation	'	'
	Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation
	The accompanying unaudited condensed consolidated financial statements include the accounts of Alion Science and Technology Corporation (a Delaware corporation), and its wholly-owned subsidiaries and have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission. Certain information and note disclosures normally included in the annual financial statements, prepared in accordance with generally accepted accounting principles in the United States of America (GAAP), have been omitted pursuant to those rules and regulations. However, the Company believes that the disclosures made are adequate to make the information presented not misleading. The statements are prepared on the accrual basis of accounting and include the accounts of Alion and its wholly-owned subsidiaries from their date of acquisition or formation. All inter-company accounts have been eliminated in consolidation. There have been no changes to Alion’s subsidiaries in the current fiscal year.	The accompanying audited consolidated financial statements include the accounts of Alion Science and Technology Corporation (a Delaware corporation) and its wholly-owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles on the accrual basis of accounting. The statements include the accounts of Alion and its wholly-owned subsidiaries from date of formation or acquisition. All inter-company accounts have been eliminated in consolidation. The wholly-owned subsidiaries are:
	In management’s opinion, the accompanying unaudited condensed consolidated financial statements reflect all adjustments consisting of normal recurring adjustments and reclassifications that are necessary for fair presentation of the periods presented. The results for the three months ended December 31, 2013 are not necessarily indicative of the results to be expected for the full fiscal year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s latest annual report on Form 10-K for the year ended September 30, 2013.
			•	Innovative Technology Solutions Corporation (ITSC) – acquired October 2003
			•	Alion - IPS Corporation (IPS) – acquired February 2004
			•	Alion - METI Corporation (METI) – acquired February 2005
			•	Alion - CATI Corporation (CATI) – acquired February 2005
			•	Alion International Corporation (Alion International) – established February 2005
			•	Alion Science and Technology (Canada) Corporation – established February 2005
			•	Alion - JJMA Corporation (JJMA) – acquired April 2005
			•	Alion - BMH Corporation (BMH) – acquired February 2006
			•	Washington Consulting, Inc. (WCI) – acquired February 2006
			•	Alion—MA&D Corporation (MA&D) – acquired May 2006
			•	Alion Offshore Services, Inc. (Alion Offshore) – established May 2006
			•	Washington Consulting Government Services, Inc. (WCGS) – established July 2007
			•	Alion Asia Corporation (Alion Asia) – established May 2012
			•	Alion Maritime India Private Limited (Alion India) – established May 2013
Fiscal, Quarter and Interim Periods	'	'
	Fiscal, Quarter and Interim Periods	Fiscal, Quarter and Interim Periods
	Alion’s fiscal year ends on September 30. The Company operates based on a three-month quarter, four-quarter fiscal year with quarters ending December 31, March 31, June 30, and September 30.	Alion’s fiscal year ends on September 30. The Company operates based on a three-month quarter, four-quarter fiscal year with quarters ending December 31, March 31, June 30, and September 30.
Use of Estimates	'	'
	Use of Estimates	Use of Estimates
	Preparing financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect amounts reported for assets and liabilities, disclosures of contingent assets and liabilities as of financial statement dates and amounts reported for operating results for each period presented. Actual results are likely to differ from those estimates, but management does not believe such differences will materially affect Alion’s financial position, results of operations, or cash flows.	Preparing financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect amounts reported for assets and liabilities, disclosures of contingent assets and liabilities as of financial statement dates and amounts reported for operating results for each period presented. Actual results are likely to differ from those estimates, but management does not believe such differences will materially affect Alion’s financial position, results of operations, or cash flows.
Going Concern Assumption	'	'
	Going Concern Assumption	Going Concern Assumption
	The accompanying financial statements are prepared on the going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Alion has a history of losses that has resulted, in part, in the Company not having the means to repay the principal associated with our Secured and Unsecured Notes as they come due on November 1, 2014 and February 1, 2015, respectively. In the first quarter of fiscal 2014, our Secured Notes were reclassified to current liabilities based on their November 1, 2014 maturity. Our Unsecured Notes will be reclassified to current liabilities in the second quarter of fiscal 2014.	The accompanying financial statements are prepared on the going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Alion has a history of losses that has resulted, in part, in the Company not having the means to repay the principal associated with our Secured and Unsecured Notes as they come due on November 1, 2014 and February 1, 2015, respectively. Further, liabilities in excess of our assets makes refinancing our debt more difficult and expensive, and an insufficient level of cash flow from operating activities to repay the Secured and Unsecured Notes at maturity, raises substantial doubt as to the Company’s ability to continue as a going concern.
	Our liabilities exceed our assets which makes refinancing our debt more difficult and expensive. Operating cash flow is insufficient to repay the Secured and Unsecured Notes at maturity, which raises substantial doubt as to the Company’s ability to continue as a going concern.	Management’s current forecasts of future results could differ materially due to general economic uncertainties, sequestration’s effect on government spending levels in the coming fiscal year, collections delays from the October 2013 government shutdown and risks associated with future federal government procurement and contracting actions. Management’s cash flow projections indicate that absent a refinancing transaction or series of transactions, the Company will be unable to pay the principal and accumulated unpaid interest on its Secured and Unsecured Notes when those instruments come due in November 2014 and February 2015.
	Management’s current forecasts of future results could differ materially due to general economic uncertainties, sequestration’s effect on government spending levels in the coming fiscal year, collections delays from the October 2013 government shutdown and risks associated with future federal government procurement and contracting actions. Management’s cash flow projections indicate that absent a refinancing transaction or series of transactions, the Company will be unable to pay the principal and accumulated unpaid interest on its Secured and Unsecured Notes when those instruments come due in November 2014 and February 2015.	Alion depends heavily on federal government prime contracts and subcontracts which account for nearly all the Company’s revenue. Interruptions in the government funding process, whether from federal budget delays, debt ceiling limitations, government shutdowns, sequestration or Department of Defense spending cuts could materially adversely affect the Company’s revenue and cash flows for the coming fiscal year and beyond. This could cause Alion to be unable to fund operations, meet debt service requirements or comply with the Credit Agreement’s Consolidated EBITDA covenant.
	Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of receiving an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this financial covenant. The Company paid no fee for this waiver.	Our Credit Agreement financial statement covenant requires an audit opinion without a “going concern” explanatory note or any similar qualification or exception and without any qualification or exception as to the scope of such audit. In anticipation of receiving an audit opinion including a “going concern” explanatory note, in December 2013 Alion and its Credit Agreement lenders agreed to waive this financial covenant. The Company paid no fee for this waiver
		If Alion were unable to meet the Credit Agreement Consolidated EBITDA covenant, the Company would be unable to borrow funds under the revolving credit facility which would remove a source of liquidity for the Company. Alion could be required to immediately repay any amount then outstanding under the Credit Agreement. The Company could seek an additional covenant waiver or an amendment to the Credit Agreement in order to preserve its ability to borrow funds as and when needed. The Credit Agreement expires on August 22, 2014. Management can provide no assurance that Alion would be able to obtain an amendment or waiver, or if one were available, that the terms would be favorable. If the Company were unable to obtain a requested waiver or amendment, it might be unable to pay its debts as they became due. In each of the past three fiscal years, Alion generated sufficient cash flow from operations to fulfill its financial commitments, including debt service.
	Alion depends heavily on federal government prime contracts and subcontracts which account for nearly all the Company’s revenue. Interruptions in the government funding process, whether from federal budget delays, debt ceiling limitations, government shutdowns, sequestration or Department of Defense spending cuts could materially adversely affect the Company’s revenue and cash flows for the coming fiscal year and beyond. This could cause Alion to be unable to fund operations, meet debt service requirements or comply with the Credit Agreement’s Consolidated EBITDA covenant.	Management is actively engaged in identifying additional potential sources of cash to refinance, retire or amend Alion’s existing debt agreements. We have reached a preliminary understanding with the holders of a majority of our outstanding Unsecured Notes regarding potential refinancing transactions involving our outstanding indebtedness and are negotiating a definitive agreement. However, Management can provide no assurance that Alion will be able to conclude a refinancing of its Unsecured Notes or that additional financing will be available to retire or replace its Secured Notes, and if available, that terms of any transaction would be favorable.
	If Alion were unable to meet the Credit Agreement Consolidated EBITDA covenant, the Company would be unable to borrow funds under the revolving credit facility which would remove a source of liquidity for the Company. Alion could be required to immediately repay any amount then outstanding under the Credit Agreement. The Company could seek an additional covenant waiver or an amendment to the Credit Agreement in order to preserve its ability to borrow funds as and when needed. The Credit Agreement expires on August 22, 2014. Management can provide no assurance that Alion would be able to obtain an amendment or waiver, or if one were available, that the terms would be favorable. If the Company were unable to obtain a requested waiver or amendment, it might be unable to pay its debts as they became due. In each of the past three fiscal years, Alion generated sufficient cash flow from operations to fulfill its financial commitments, including debt service.	On the basis of these risks and uncertainties, management has determined that there is substantial doubt about the Company’s ability to continue as a going concern. Alion’s audited consolidated financial statements do not include any adjustments to reflect the possible effects on the recoverability of assets or the amounts of liabilities that may result from resolving uncertainties about the Company’s ability to continue as a going concern.
	Management is actively engaged in efforts to refinance, retire or amend Alion’s existing debt agreements. On December 24, 2013, we executed a Refinancing Support Agreement with the holders of a majority of our outstanding Unsecured Notes regarding potential transactions to refinance our outstanding indebtedness. Management can provide no assurance that Alion will be able to conclude a refinancing of its Unsecured Notes or that additional financing will be available to retire or replace the Secured Notes, and if available, that terms of any transaction would be favorable.
	On the basis of these risks and uncertainties, management has determined that there is substantial doubt about the Company’s ability to continue as a going concern. Alion’s unaudited condensed consolidated financial statements do not include any adjustments to reflect the possible effects on the recoverability of assets or the amounts of liabilities that may result from resolving uncertainties about the Company’s ability to continue as a going concern.
Revenue Recognition	'	'
	Revenue Recognition	Revenue Recognition
	Alion derives its revenue from delivering technology services under three types of contracts. Some contracts provide for reimbursement of costs plus fees; others are fixed-price or time-and-material type contracts. We recognize revenue when a contract has been executed, the contract price is fixed or determinable, delivery of services or products has occurred, and our ability to collect the contract price is considered reasonably assured. Alion applies the percentage-of-completion method in Accounting Standards Codification (ASC) 605 – Revenue Recognition to recognize revenue.	Alion derives its revenue from delivering technology services under three types of contracts. Some contracts provide for reimbursement of costs plus fees; others are fixed-price or time-and-material type contracts. We recognize revenue when a contract has been executed, the contract price is fixed or determinable, delivery of services or products has occurred, and our ability to collect the contract price is considered reasonably assured. Alion applies the percentage-of-completion method in Accounting Standards Codification (ASC) 605 – Revenue Recognition to recognize revenue.
	Alion recognizes revenue on cost-reimbursement contracts as it incurs costs and includes estimated fees earned. The Company recognizes time-and-material contract revenue at negotiated, fixed, contractually billable rates as it delivers labor hours and incurs other direct expenses. We use various performance measures under the percentage-of-completion method to recognize revenue for fixed-price contracts. Estimating contract costs at completion and recognizing revenue appropriately involve significant management estimates. Actual costs may differ from estimated costs and affect estimated profitability and revenue recognition timing. From time to time, facts develop that require us to revise estimated total costs or expected revenue. We record the cumulative effect of revised estimates in the period when the facts requiring revised estimates become known. We recognize the full amount of anticipated losses on any contract in the period a loss becomes known. For each of the periods presented, the cumulative effects of revised estimates were immaterial to the Company’s financial performance.
	U.S. federal government contracts are subject to periodic funding by our contracting agency customers. A customer may fund a contract at inception or incrementally throughout the period of performance as services are provided. If we determine contract funding is not probable, we defer revenue recognition until realization is probable. The federal government can audit Alion’s contract costs and adjust amounts through negotiation. The federal government considers Alion a major contractor and maintains an office on site. The Defense Contract Audit Agency (DCAA) is currently auditing our 2007 claimed indirect costs. We are negotiating our 2006 indirect rates and have settled our rates through 2005. We timely submitted our indirect cost proposals for all open fiscal years. We have recorded revenue on federal government contracts in amounts we expect to realize.	Alion recognizes revenue on cost-reimbursement contracts as it incurs costs and includes estimated fees earned. The Company recognizes time-and-material contract revenue at negotiated, fixed, contractually billable rates as it delivers labor hours and incurs other direct expenses. We use various performance measures under the percentage-of-completion method to recognize revenue for fixed-price contracts. Estimating contract costs at completion and recognizing revenue appropriately involve significant management estimates. Actual costs may differ from estimated costs and affect estimated profitability and revenue recognition timing. From time to time, facts develop that require us to revise estimated total costs or expected revenue. We record the cumulative effect of revised estimates in the period when the facts requiring revised estimates become known. We recognize the full amount of anticipated losses on any contract in the period a loss becomes known. For each of the periods presented, the cumulative effects of revised estimates were immaterial to the Company’s financial performance.
	We recognize revenue on unpriced change orders as we incur expenses and only to the extent it is probable we will recover such costs. The Company recognizes revenue in excess of costs on unpriced change orders only when management can also estimate beyond a reasonable doubt the amount of excess and experience provides a sufficient basis for recognition. Alion recognizes revenue on claims as expenses are incurred and only to the extent it is probable we will recover such costs and can reliably estimate the amount we will recover.	U.S. federal government contracts are subject to periodic funding by our contracting agency customers. A customer may fund a contract at inception or incrementally throughout the period of performance as services are provided. If we determine contract funding is not probable, we defer revenue recognition until realization is probable. The federal government can audit Alion’s contract costs and adjust amounts through negotiation. The federal government considers Alion a major contractor and maintains an office on site. The Defense Contract Audit Agency (DCAA) is currently auditing our 2007 claimed indirect costs. We are negotiating our 2006 indirect rates and have settled our rates through 2005. We timely submitted our indirect cost proposals for all open fiscal years. We have recorded revenue on federal government contracts in amounts we expect to realize.
		We recognize revenue on unpriced change orders as we incur expenses and only to the extent it is probable we will recover such costs. The Company recognizes revenue in excess of costs on unpriced change orders only when management can also estimate beyond a reasonable doubt the amount of excess and experience provides a sufficient basis for recognition. Alion recognizes revenue on claims as expenses are incurred and only to the extent it is probable we will recover such costs and can reliably estimate the amount we will recover.
Income Taxes	'	'
	Income Taxes	Income Taxes
	Alion accounts for income taxes by applying the provisions in currently enacted tax laws. We determine deferred income taxes based on the estimated future tax effects of differences between the financial statement and tax bases of our assets and liabilities. Deferred income tax provisions and benefits change as assets or liabilities change from year to year. In providing for deferred taxes, Alion considers the tax regulations of the jurisdictions where we operate; estimated future taxable income; and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies change, the carrying value of deferred tax assets and liabilities may require adjustment.	Alion accounts for income taxes by applying the provisions in currently enacted tax laws. We determine deferred income taxes based on the estimated future tax effects of differences between the financial statement and tax bases of our assets and liabilities. Deferred income tax provisions and benefits change as assets or liabilities change from year to year. In providing for deferred taxes, Alion considers the tax regulations of the jurisdictions where we operate; estimated future taxable income; and available tax planning strategies. If tax regulations, operating results or the ability to implement tax-planning strategies change, the carrying value of deferred tax assets and liabilities may require adjustment.
	Alion has a history of operating losses for both tax and financial statement purposes. The Company has recorded valuation allowances equal to deferred tax assets based on the likelihood that we may not be able to realize the value of these assets. Alion recognizes the benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain our position following an audit. For tax positions meeting the “more likely than not” threshold, we recognize the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.	Alion has a history of operating losses for both tax and financial statement purposes. The Company has recorded valuation allowances equal to deferred tax assets based on the likelihood that we may not be able to realize the value of these assets. Alion recognizes the benefit of a tax position only after determining that the relevant tax authority would “more likely than not” sustain our position following an audit. For tax positions meeting the “more likely than not” threshold, we recognize the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
Cash and Cash Equivalents	'	'
	Cash and Cash Equivalents	Cash and Cash Equivalents
	The Company considers cash in banks, and deposits with financial institutions with maturities of three months or less at time of purchase which it can liquidate without prior notice or penalty, to be cash and cash equivalents.	The Company considers cash in banks, and deposits with financial institutions with maturities of three months or less at time of purchase which it can liquidate without prior notice or penalty, to be cash and cash equivalents.
Accounts Receivable and Billings in Excess of Revenue Earned	'	'
	Accounts Receivable and Billings in Excess of Revenue Earned	Accounts Receivable and Billings in Excess of Revenue Earned
	Accounts receivable include billed accounts receivable and unbilled receivables. Unbilled receivables consist of costs and fees which are billable upon occurrence of a specific event, amounts billable after the balance sheet date and revenue in excess of billings on uncompleted contracts (accumulated project expenses and fees which were not billed or were not currently billable as of the date of the consolidated balance sheet). Unbilled accounts receivable include revenue recognized for customer-requested work Alion performed on new and existing contracts for which the Company had not received contracts or contract modifications. Accounts receivable are stated as estimated realized value. The allowance for doubtful accounts is Alion’s best estimate of the amount of probable losses in the Company’s existing billed and unbilled accounts receivable. The Company determines the allowance using specific identification and historical write-off experience based on receivable age. Billings in excess of revenue and advance collections from customers represent amounts received from or billed to customers in excess of project revenue recognized to date.	Accounts receivable include billed accounts receivable and unbilled receivables. Unbilled receivables consist of costs and fees which are billable upon occurrence of a specific event, amounts billable after the balance sheet date and revenue in excess of billings on uncompleted contracts (accumulated project expenses and fees which were not billed or were not currently billable as of the date of the consolidated balance sheet). Unbilled accounts receivable include revenue recognized for customer-requested work Alion performed on new and existing contracts for which the Company had not received contracts or contract modifications. Accounts receivable are stated as estimated realized value. The allowance for doubtful accounts is Alion’s best estimate of the amount of probable losses in the Company’s existing billed and unbilled accounts receivable. The Company determines the allowance using specific identification and historical write-off experience based on receivable age. Billings in excess of revenue and advance collections from customers represent amounts received from or billed to customers in excess of project revenue recognized to date.
Property, Plant and Equipment	'	'
	Property, Plant and Equipment	Property, Plant and Equipment
	Leasehold improvements, software and equipment are recorded at cost. Maintenance and repairs that do not add significant value or significantly lengthen an asset’s useful life are charged to current operations. Software and equipment are depreciated on the straight-line method over their estimated useful lives (typically 3 years for software and 5 years for equipment). Leasehold improvements are amortized on the straight-line method over the shorter of the asset’s estimated useful life or the life of the lease. Upon sale or retirement of an asset, costs and related accumulated depreciation are deducted from the accounts, and any gain or loss is recognized in the unaudited condensed consolidated statements of operations.	Leasehold improvements, software and equipment are recorded at cost. Maintenance and repairs that do not add significant value or significantly lengthen an asset’s useful life are charged to current operations. Software and equipment are depreciated on the straight-line method over their estimated useful lives (typically 3 years for software and 5 years for equipment). Leasehold improvements are amortized on the straight-line method over the shorter of the asset’s estimated useful life or the life of the lease. Upon sale or retirement of an asset, costs and related accumulated depreciation are deducted from the accounts, and any gain or loss is recognized in the audited consolidated statements of operations.
Goodwill	'	'
	Goodwill	Goodwill
	Alion assigns the purchase price paid to acquire the stock or assets of a business to the net assets acquired based on the estimated fair value of assets acquired and liabilities assumed. Goodwill is the purchase price in excess of the estimated fair value of the tangible net assets and separately identified intangible assets acquired. There have been no changes to goodwill carrying value this year.	Alion assigns the purchase price paid to acquire the stock or assets of a business to the net assets acquired based on the estimated fair value of assets acquired and liabilities assumed. Goodwill is the purchase price in excess of the estimated fair value of the tangible net assets and separately identified intangible assets acquired. There have been no changes to goodwill carrying value this year.
	The Company accounts for goodwill and other intangible assets in accordance with the provisions of ASC 350 – Intangibles-Goodwill and Other. Alion operates in one segment and tests goodwill at the reporting unit level. There are two reporting units. We review goodwill for impairment in the fourth quarter each year, and whenever events or circumstances indicate goodwill might be impaired. We are required to recognize an impairment loss to the extent our goodwill carrying value at the reporting unit level exceeds fair value. Evaluating goodwill involves significant management estimates. To date, our annual reviews have resulted in no goodwill impairment adjustments. See Note 8 for a detailed discussion of the Company’s goodwill impairment testing process.	The Company accounts for goodwill and other intangible assets in accordance with the provisions of ASC 350 – Intangibles-Goodwill and Other. Alion operates in one segment and tests goodwill at the reporting unit level. There are two reporting units. We review goodwill for impairment in the fourth quarter each year, and whenever events or circumstances indicate goodwill might be impaired. We are required to recognize an impairment loss to the extent our goodwill carrying value at the reporting unit level exceeds fair value. Evaluating goodwill involves significant management estimates. To date, our annual reviews have resulted in no goodwill impairment adjustments. See Note 9 for a detailed discussion of the Company’s goodwill impairment testing process.
Intangible Assets	'	'
	Intangible Assets	Intangible Assets
	Alion amortizes intangible assets as it consumes economic benefits over estimated useful lives. As of December 31, 2013, the Company had approximately $1.7 million in net intangible assets, including contracts purchased in the JJMA acquisition and purchased software licenses. The JJMA contract portfolio has a remaining useful life of approximately 1.5 years.	Alion amortizes intangible assets as it consumes economic benefits over estimated useful lives. As of September 30, 2013, the Company had approximately $2.0 million in net intangible assets, including contracts purchased in the JJMA acquisition and purchased software licenses. The JJMA contract portfolio has a remaining useful life of approximately 1.6 years.
Redeemable Common Stock	'	'
	Redeemable Common Stock	Redeemable Common Stock
	There is no public market for Alion’s redeemable common stock and therefore no observable price for its equity, individually or in the aggregate. The Employee Stock Ownership Plan (ESOP) Trust holds all the Company’s outstanding common stock. Under certain circumstances, ESOP beneficiaries can require the ESOP Trust to distribute the value of their beneficial interests. The Internal Revenue Code (IRC) and the Employee Retirement Income Security Act (ERISA) require the Company to offer ESOP participants who receive Alion common stock a liquidity put right. The put right requires the Company to purchase distributed shares at their then- current fair market value at any time during two put option periods. Common stock distributed by the ESOP Trust is subject to a right of first refusal. Prior to any subsequent transfer, shares must first be offered to the Company and then to the ESOP Trust. Eventual redemption of shares of Alion common stock as a result of distributions is outside the Company’s control. Therefore, Alion classifies its outstanding shares of redeemable common stock as other than permanent equity.	There is no public market for Alion’s redeemable common stock and therefore no observable price for its equity, individually or in the aggregate. The Employee Stock Ownership Plan (ESOP) Trust holds all the Company’s outstanding common stock. Under certain circumstances, ESOP beneficiaries can require the ESOP Trust to distribute the value of their beneficial interests. The Internal Revenue Code (IRC) and the Employee Retirement Income Security Act (ERISA) require the Company to offer ESOP participants who receive Alion common stock a liquidity put right. The put right requires the Company to purchase distributed shares at their then-current fair market value at any time during two put option periods. Common stock distributed by the ESOP Trust is subject to a right of first refusal. Prior to any subsequent transfer, shares must first be offered to the Company and then to the ESOP Trust. Eventual redemption of shares of Alion common stock as a result of distributions is outside the Company’s control. Therefore, Alion classifies its outstanding shares of redeemable common stock as other than permanent equity.
	At each reporting date, Alion is required to increase or decrease the reported value of its outstanding common stock to reflect its estimated redemption value. Management estimates the value of Alion’s obligation to repurchase its outstanding shares of redeemable common stock by considering, in part, the most recent price at which the Company was able to sell shares to the ESOP Trust. The reported value of outstanding redeemable common stock equals the current share price multiplied by total shares issued and outstanding.	At each reporting date, Alion is required to increase or decrease the reported value of its outstanding common stock to reflect its estimated redemption value. Management estimates the value of Alion’s obligation to repurchase its outstanding shares of redeemable common stock by considering, in part, the most recent price at which the Company was able to sell shares to the ESOP Trust. The reported value of outstanding redeemable common stock equals the current share price multiplied by total shares issued and outstanding.
	In its fiduciary capacity, the ESOP Trustee is independent of the Company and its management. Consistent with its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the ESOP Trustee may acquire or dispose of investments in Alion common stock. The Audit and Finance Committee of Alion’s Board of Directors reviews the reasonableness of the amount management has determined Alion should recognize for the Company’s obligation to repurchase shares of its outstanding redeemable common stock. The Audit and Finance Committee considers various factors in its review, including, in part, the most recent valuation report prepared for, and the share price selected by the ESOP Trustee.	In its fiduciary capacity, the ESOP Trustee is independent of the Company and its management. Consistent with its fiduciary responsibilities, the ESOP Trustee retains an independent third party valuation firm to assist it in determining the fair market value (share price) at which the ESOP Trustee may acquire or dispose of investments in Alion common stock. The Audit and Finance Committee of Alion’s Board of Directors reviews the reasonableness of the amount management has determined Alion should recognize for the Company’s obligation to repurchase shares of its outstanding redeemable common stock. The Audit and Finance Committee considers various factors in its review, including, in part, the most recent valuation report prepared for, and the share price selected by the ESOP Trustee.
	Alion records changes in the reported value of its outstanding common stock through an offsetting charge or credit to accumulated deficit. The Company recognizes changes in the fair value of its redeemable common stock on March 31 and September 30 each year. The accumulated deficit at December 31, 2013, included a $67.5 million cumulative benefit for changes in share price which reduced the Company’s aggregate share redemption obligation. Outstanding redeemable common stock had an aggregate fair value of approximately $61.9 million as of December 31, 2013.
		Alion records changes in the reported value of its outstanding common stock through an offsetting charge or credit to accumulated deficit. The Company recognizes changes in the fair value of its redeemable common stock on March 31 and September 30 each year. The accumulated deficit at September 30, 2013, included a $67.5 million cumulative benefit for changes in share price which reduced the Company’s aggregate share redemption obligation. Outstanding redeemable common stock had an aggregate fair value of approximately $61.9 million as of September 30, 2013.
Concentration of Credit Risk	'	'
	Concentration of Credit Risk	Concentration of Credit Risk
	Alion is subject to credit risk for its cash equivalents and accounts receivable. The Company believes the high credit quality of its cash equivalent investments limits its credit risk with respect to such investments. Alion believes its concentration of credit risk with respect to accounts receivable is limited as the receivables are principally due from the federal government. Approximately 21% of the Company’s receivables are due from commercial customers including other prime contractors.	Alion is subject to credit risk for its cash equivalents and accounts receivable. The Company believes the high credit quality of its cash equivalent investments limits its credit risk with respect to such investments. Alion believes its concentration of credit risk with respect to accounts receivable is limited as the receivables are principally due from the federal government. Approximately 22% of the Company’s receivables are due from commercial customers including other prime contractors.
Fair Value of Financial Instruments	'	'
	Fair Value of Financial Instruments	Fair Value of Financial Instruments
	Alion is required to disclose the fair value of its financial instruments but is not required to record its senior long-term debt at fair value. See Note 10 for a discussion of Alion’s current and long-term debt and Note 11 for the related fair value disclosures. The fair value of cash, cash equivalents, accounts payable and accounts receivable does not differ materially from carrying value because of the short maturity of those instruments.	Alion is required to disclose the fair value of its financial instruments, but is not required to record its senior long term debt at fair value. See Note 11 for a discussion of Alion’s long term debt and Note 12 for the related fair value disclosures. The fair value of cash, cash equivalents, accounts payable and accounts receivable is not materially different from carrying value because of the short maturity of those instruments.
Off-Balance Sheet Financing Arrangements	'	'
	Off-Balance Sheet Financing Arrangements	Off-Balance Sheet Financing Arrangements
	Alion accounts for operating leases entered into in the routine course of business in accordance with ASC 840 – Leases. We have no off-balance sheet financing arrangements other than operating leases and letters of credit under our revolving credit facility. Alion has no relationship with any unconsolidated or special purpose entity and has not issued any associated guarantees.	Alion accounts for operating leases entered into in the routine course of business in accordance with ASC 840 Leases. We have no off-balance sheet financing arrangements other than operating leases and letters of credit under our revolving credit facility. Alion has no relationship with any unconsolidated or special purpose entity and has not issued any guarantees.
Recently Issued Accounting Pronouncements	'	'
		Recently Issued Accounting Pronouncements
		In July 2013, FASB issued Accounting Standards Update 2013-11 (ASU 2013-11)—Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. ASU 2013-11 updates Accounting Standards Codification Topic 740 – Income Taxes and is intended to eliminate diversity in accounting practice. In general, ASU 2013-11 requires an entity to reduce deferred tax assets for unrecognized tax benefits related to net operating loss or tax credit carryforwards. An entity is to present unrecognized tax benefits as a liability when: (1) the related net operating loss or tax credit carryforward is unavailable to settle the liability; or (2) tax law permits and the entity intends not to use its deferred tax assets to offset taxes arising from disallowing the entity’s tax position. ASU 2013-11 affects presentation of amounts and does not affect income tax expense. Management does not believe that adopting ASU 2013-11 will affect the Company’s operating results, financial position or cash flows.
		In January 2013, the FASB issued Accounting Standards Update 2013-01 (ASU 2013-01) Balance Sheet Topic (Topic 210)—Clarifying the Scope and Disclosures About Offsetting Assets and Liabilities. ASU 2013-01 is effective for fiscal years beginning after January 1, 2013 and provides guidance on what disclosures to make about offsetting balances. Alion currently does not offset any significant balances and has no related disclosure. The Company does not believe adopting ASU 2013-01 will affect Alion’s consolidated financial position or operating results.
Segment Reporting	'	'
		Management applied the guidance in ASC 350 and the related guidance in ASC Topic 280 Segment Reporting to analyze Alion’s reporting units to determine the appropriate level at which to test goodwill for potential impairment. The Company employs a reasonable, supportable and consistent method to assign goodwill to reporting units expected to benefit from the synergies arising from acquisitions. Alion determined reporting unit goodwill in a manner similar to the way it determines goodwill in a purchase allocation by using fair value to determine reporting unit purchase price, assets, liabilities and goodwill. Reporting unit residual fair value after this allocation is the implied fair value of reporting unit goodwill. The Company allocates the goodwill related to acquisitions on a specific identification basis consistent with reporting unit structure.
Fair Value Measurement	'	'
		ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in
		an orderly transaction between market participants at the measurement date. It establishes a fair value hierarchy and a framework which requires categorizing assets and liabilities into one of three levels based on the assumptions (inputs) used in valuing the asset or liability. Level 1 provides the most reliable measure of fair value, while Level 3 generally requires significant management judgment. Level 1inputs are unadjusted, quoted market prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in inactive markets. Level 3 inputs include unobservable inputs that are supported by little, infrequent, or no market activity and reflect management’s own assumptions about inputs used in pricing the asset or liability. The Company uses the following valuation techniques to measure fair value.
		Level 1 primarily consists of financial instruments, such as overnight bank re-purchase agreements or money market mutual funds whose value is based on quoted market prices published by financial institutions, exchange funds, exchange-traded instruments and listed equities.
		Level 2 assets include U.S. Government and agency securities whose valuations are based on market prices from a variety of industry-standard data providers or pricing that considers various assumptions, including time value, yield curve, volatility factors, credit spreads, default rates, loss severity, current market and contractual prices for the underlying instruments, and broker and dealer quotes. All are observable in the market or can be derived principally from or corroborated by observable market data for which the Company can obtain independent external valuation information.
		Level 3 consists of unobservable inputs. Assets and liabilities are considered Level 3 when their fair value inputs are unobservable or not available, including situations involving limited market activity, where determination of fair value requires significant judgment or estimation.

Accounts_Receivable_Tables1

Accounts Receivable (Tables)	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Receivables [Abstract]	'							'
Accounts Receivable	'							'
	Accounts receivable at December 31, 2013 and September 30, 2013 consisted of the following:							Accounts receivable at September 30 consisted of the following:
		December 31,			September 30,				September 30,
		2013			2013				2013			2012
		(In thousands)							(In thousands)
	Billed receivables and amounts billable as of the balance sheet date	$	104,581		$	102,211		Billed receivables and amounts billable as of the balance sheet date	$	102,211		$	94,028
	Unbilled receivables:							Unbilled receivables:
	Amounts billable after the balance sheet date		28,107			36,693		Amounts billable after the balance sheet date		36,693			48,730
	Revenues recorded in excess of milestone billings on fixed price contracts		3,825			3,289		Revenues recorded in excess of milestone billings on fixed price contracts		3,289			2,666
	Revenues recorded in excess of estimated contract value or funding		17,803			14,605		Revenues recorded in excess of estimated contract value or funding		14,605			18,998
	Retainages and other amounts billable upon contract completion		18,635			19,557		Retainages and other amounts billable upon contract completion		19,557			15,016
	Allowance for doubtful accounts		(3,988	)		(3,751	)	Allowance for doubtful accounts		(3,751	)		(4,145	)
	Total Accounts Receivable	$	168,963		$	172,604		Total Accounts Receivable	$	172,604		$	175,293

Property_Plant_and_Equipment_T1

Property, Plant and Equipment (Tables)	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Property Plant And Equipment [Abstract]	'							'
Property, Plant and Equipment	'							'
	Property, Plant and Equipment							Property, Plant and Equipment
		December 31,			September 30,				September 30,
		2013			2013				2013			2012
		(In thousands)							(In thousands)
	Leasehold improvements	$	12,603		$	12,984		Leasehold improvements	$	12,984		$	12,168
	Equipment and software		35,314			35,203		Equipment and software		35,203			35,562
	Total cost		47,917			48,187		Total cost		48,187			47,730
	Less: accumulated depreciation and amortization		(38,847	)		(38,519	)	Less: accumulated depreciation and amortization		(38,519	)		(37,125	)
	Net Property, Plant and Equipment	$	9,070		$	9,668		Net Property, Plant and Equipment	$	9,668		$	10,605

Intangible_Assets_Tables1

Intangible Assets (Tables)	3 Months Ended															12 Months Ended
	Dec. 31, 2013															Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'															'
Intangible Assets	'															'
	The table below shows intangible assets as of December 31, 2013 and September 30, 2013.															The table below shows the intangible assets as of September 30, 2013 and 2012.
		December 31, 2013							September 30, 2013								September 30, 2013							September 30, 2012
		Gross		Accumulated			Net		Gross		Accumulated			Net			Gross		Accumulated			Net		Gross		Accumulated			Net
				Amortization							Amortization								Amortization							Amortization
		(In thousands)															(In thousands)
	Purchased contracts	$	111,635	$	(110,015	)	$	1,620	$	111,635	$	(109,795	)	$	1,840	Purchased contracts	$	111,635		(109,795	)		1,840	$	111,635	$	(106,935	)	$	4,700
	Internal use software and engineering designs		3,182		(3,067	)		115		3,182		(2,982	)		200	Internal use software and engineering designs		3,182		(2,982	)		200		3,182		(2,640	)		542
	Total	$	114,817	$	(113,082	)	$	1,735	$	114,817	$	(112,777	)	$	2,040	Total	$	114,817		(112,777	)		2,040	$	114,817	$	(109,575	)	$	5,242
Estimated Aggregate Amortization Expense	'															'
	Estimated aggregate amortization expense for the next five years and thereafter is as follows.															Estimated aggregate amortization expense for the next five years and thereafter is as follows.
		(In thousands)														Fiscal year ending	(In thousands)
																September 30,
	2014 (for the remainder of the fiscal year)	$	773													2014		1,079
	2015		737													2015		736
	2016		141													2016		141
	2017		51													2017		51
	2018		33													2018		33
	2019		—
	Thereafter		—														$	2,040
		$	1,735

LongTerm_Debt_Tables

Long-Term Debt (Tables)	3 Months Ended								12 Months Ended
	Dec. 31, 2013								Sep. 30, 2013
Debt Disclosure [Abstract]	'								'
Interest Payable	'								'
			December 31,		September 30,
			2013		2013						September 30,
			(In thousands)								2013		2012
	Secured Notes		$	5,551	$	13,741					(In thousands)
	Unsecured Notes			10,039		4,017			Secured Notes			13,741		13,470
									Unsecured Notes		$	4,017	$	4,188
	Total		$	15,590	$	17,758
									Total		$	17,758	$	17,658
Principal Repayments	'								'
	As of December 31, 2013, Alion must make the following principal repayments (face value) for its outstanding debt. Unsecured Note face value exceeds carrying value and Secured Note face value exceeds carrying value. Carrying value includes debt issue costs which include the unamortized balances of: original issue discount; third-party debt issue expenses; and the initial fair value of common stock warrants issued in connection with the Secured Notes.								As of September 30, 2013, Alion must make the following principal repayments (face value) for its outstanding debt.
											2014		2015		Total
	Future Payments by Fiscal Year:		2014		2015		Total		Secured Notes and PIK Interest (1)		$	—	$	339,788	$	339,788
									Unsecured Notes (2)			—		235,000		235,000
	Secured Notes and PIK Interest(1)		$	—	$	339,788	$	339,788
	Unsecured Notes(2)			—		235,000		235,000	Total Principal Payments		$	—	$	574,788	$	574,788
	Total Principal Payments		$	—	$	574,788	$	574,788
									1	The Secured Notes due November 2014 include $310 million of debt issued in March 2010 and an estimated $29.8 million in PIK interest added to principal over the life of the notes. As of September 30, 2013, the $322.3 million carrying value on the face of the balance sheet included $310 million in principal, $19.8 million in PIK notes issued; $2.7 million in accrued PIK interest and is net of $10.3 million in aggregate unamortized debt issue costs. Initial debt issue costs consist of $7.7 million in original issue discount, $13.5 million in third-party costs and $20.8 million for the Secured Note warrants’ initial fair value.
									2	As of September 30, 2013, the Unsecured Notes due February 2015 include $235 million in principal and $1.2 million in unamortized debt issue costs (initially $7.1 million). The Company repurchased $10 million in Unsecured Notes in 2013 and $5 million in Unsecured Notes in 2011.
	1	The Secured Notes due November 2014 include $310 million of debt issued in March 2010 and an estimated $29.8 million in PIK interest added to principal over the life of the notes. As of December 31, 2013, the $326.3 million carrying value on the face of the balance sheet included $310 million in principal, $23.1 million in PIK notes issued; $1.1 million in accrued PIK interest and is net of $7.9 million in aggregate unamortized debt issue costs. Initial debt issue costs consist of $7.7 million in original issue discount, $13.5 million in third-party costs and $20.8 million for the Secured Note warrants’ initial fair value.
	2	As of December 31, 2013, the Unsecured Notes due February 2015 include $235 million in principal and approximately $1.0 million in unamortized debt issue costs (initially $7.1 million). Since issuing the Unsecured Notes, the Company has repurchased $15 million in principal.

Fair_Value_Measurement_Tables1

Fair Value Measurement (Tables)	3 Months Ended													12 Months Ended
	Dec. 31, 2013													Sep. 30, 2013
Fair Value Disclosures [Abstract]	'													'
Face Value, Net Carrying Value and Fair Value of Secured and Unsecured Notes	'													'
	The table below sets out the face value, net carrying value and fair value of Alion’s Secured and Unsecured Notes. The fair values disclosed below are based on quoted market prices for Alion’s outstanding notes. This is a Level 2 measurement.													The table below sets out the face value, net carrying value and fair value of Alion’s Secured and Unsecured Notes. The fair values disclosed below are based on quoted market prices for Alion’s outstanding notes. This is a Level 2 measurement.
		December 31, 2013						September 30, 2013							September 30, 2013						September 30, 2012
		(In thousands)													(In thousands)
		Secured			Unsecured			Secured			Unsecured				Senior			Senior			Senior			Senior
		Notes			Notes			Notes			Notes				Secured			Unsecured			Secured			Unsecured
	Face value of original notes outstanding	$	310,000		$	235,000		$	310,000		$	235,000			Notes			Notes			Notes			Notes
	PIK interest notes issued		23,086			—			19,788			—		Face value of original notes outstanding	$	310,000		$	235,000		$	310,000		$	245,000
														PIK interest notes issued		19,788			—			13,293			—
	Face value of outstanding notes	$	333,086		$	235,000		$	329,788		$	235,000
	PIK interest notes to be issued		1,111			—			2,748			—		Face value of outstanding notes	$	329,788		$	235,000		$	323,293		$	245,000
														PIK interest notes to be issued		2,748			—			2,692			—
	Face value of notes outstanding and notes to be issued	$	334,197		$	235,000		$	332,536		$	235,000
	Less: unamortized debt issue costs		(7,883	)		(962	)		(10,250	)		(1,168	)	Face value of notes outstanding and notes to be issued	$	332,536		$	235,000		$	325,985		$	245,000
														Less: unamortized debt issue costs		(10,250	)		(1,168	)		(19,483	)		(2,077	)
	Carrying value	$	326,314		$	234,038		$	322,286		$	233,832
														Carrying value	$	322,286		$	233,832		$	306,502		$	242,923
	Fair value of outstanding notes	$	339,681		$	165,894		$	335,295		$	151,928		Fair value of outstanding notes	$	335,295		$	151,928		$	303,598		$	141,605

Leases_Tables1

Leases (Tables)	3 Months Ended							12 Months Ended
	Dec. 31, 2013							Sep. 30, 2013
Leases [Abstract]	'							'
Future Minimum Lease Payments	'							'
	Alion subleases some excess capacity to subtenants under non-cancelable operating leases.							Alion subleases some excess capacity to subtenants under non-cancelable operating leases.
	Lease Payments for Fiscal Years Ending	(In thousands)						Lease Payments for Fiscal Years Ending	(In thousands)
	2014 (for the remainder of fiscal year)	$	19,497					2014	$	26,009
	2015		25,076					2015		24,875
	2016		21,183					2016		21,041
	2017		17,783					2017		17,804
	2018		14,931					2018		14,931
	2019		6,162					And thereafter		19,109
	And thereafter		12,947
								Gross lease payments	$	123,769
	Gross lease payments	$	117,579					Less: non-cancelable subtenant receipts		(1,711	)
	Less: non-cancelable subtenant receipts		(1,593	)
								Net lease payments	$	122,058
	Net lease payments	$	115,986
Composition of Total Rent Expense	'							'
	Composition of Total Rent Expense							Composition of Total Rent Expense
		Three Months Ended							September 30,
		December 31,							2013			2012			2011
		2013			2012				(In thousands)
		(In thousands)						Minimum rentals	$	21,530		$	20,639		$	21,992
	Minimum rentals	$	5,515		$	5,301		Less: Sublease rental income		(600	)		(156	)		(1,610	)
	Less: Sublease rental income		(143	)		(104	)
								Total rent expense, net	$	20,930		$	20,483		$	20,382
	Total rent expense, net	$	5,372		$	5,197

Income_Taxes_Tables1

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Provision for Income Taxes	'
	The provision for income taxes for the years ended September 30, 2013, 2012 and 2011 was:
		Fiscal Years Ended
		September 30,
		2013			2012			2011
		(In thousands)
	Current:
	Foreign		3			—			—
	Total current provision	$	3			—		$	—
	Deferred:
	Federal	$	5,740			5,740		$	5,740
	State		1,234			1,234			1,234
	Total deferred provision	$	6,974			6,974		$	6,974
	Total provision for income taxes	$	6,977			6,974		$	6,974
Components of Statutory U.S. Federal Income Tax Rate to Income Before Taxes	'
	Alion’s income tax provisions at September 30, 2013, 2012 and 2011 include the effects of state income taxes, debt extinguishment and changes in valuation allowances. The provision for income taxes for the years ended September 30, 2013, 2012 and 2011 differ from the amounts computed by applying the statutory U.S. federal income tax rate to income before taxes as a result of the following:
		Fiscal Years Ended September 30,
		2013						2012						2011
		(Dollars in thousands)
	Expected federal income tax (benefit)		35	%	$	(10,365	)		35	%	$	(12,066	)		35	%	$	(13,093	)
	State income taxes (net of federal benefit)		4.5	%		(1,325	)		4.5	%		(1,539	)		4.5	%		(1,666	)
	Nondeductible expenses		(0.4	%)		105			(0.4	%)		146			(0.6	%)		232
	Provision to return true-ups		(0.1	%)		15			(0.8	%)		286			(0.2	%)		84
	Tax credits		0.3	%		(79	)		0	%		—			0	%		—
	Changes in valuation allowance		(62.9	%)		18,626			(58.4	%)		20,147			(57.2	%)		21,417
	Income tax expense (benefit)		(23.6	%)	$	6,977			(20.2	%)	$	6,974			(18.6	%)	$	6,974
Components of Deferred Tax Assets and Deferred Tax Liabilities	'
	At September 30, 2013 and 2012, the components of deferred tax assets and deferred tax liabilities were:
		September 30,
		2013			2012
		(In thousands)
	Deferred tax assets:
	Accrued expenses and reserves	$	9,228		$	11,206
	Intangible amortization		13,185			14,305
	Deferred rent		3,680			3,398
	Deferred wages		4,060			3,954
	Depreciation and leases		4,375			3,226
	Carryforwards and tax credits		62,487			42,300
	Other		25			25
	Gross deferred tax assets	$	97,040		$	78,414
	Less Valuation		(97,040	)		(78,414	)
	Deferred tax liabilities:
	Goodwill		(58,130	)		(51,156	)
	Net deferred tax asset/(liability)	$	(58,130	)	$	(51,156	)

Segment_Information_and_Custom1

Segment Information and Customer Concentration (Tables)	12 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Five Prime Contracts Represented Over Fifty Percentage of Our Revenue	'
	The following five prime contracts represented over 50% of our revenue for the past three years.
			Fiscal Years Ended
			September 30,
	Government Agency	Contract	2013			2012			2011
	DoD—Defense Information Systems Agency	Weapons System Information Analysis Center for the Defense Information Systems Agency (ID/IQ contract vehicle)		27.6	%		17.1	%		8.2	%
	DoD—U.S. Navy	Seaport-E Multiple Award Contract for the Naval Sea Systems Command (ID/IQ contract vehicle)		20.7	%		20.1	%		13.5	%
	DoD—U.S. Air Force	Technical and Analytical Support for the U.S. Air Force		8.4	%		9.9	%		11.2	%
	DoD—U.S. Navy	Naval Sea Systems Command Surface Ships Life Cycle Program Management and Engineering Support		7.2	%		5.8	%		N/A
	DoD—Defense Information Systems Agency	Modeling and Simulation Information Analysis Center for the Defense Information Systems Agency (ID/IQ contract vehicle)		2.5	%		8.1	%		14.1	%

GuarantorNonguarantor_Condense1

Guarantor/Non-guarantor Condensed Consolidated Financial Information (Tables)	3 Months Ended																12 Months Ended
	Dec. 31, 2013																Sep. 30, 2013
Text Block [Abstract]	'																'
Condensed Consolidating Balance Sheet	'																'
	Condensed Consolidating Balance Sheet as of December 31, 2013 (unaudited)																Condensed Consolidating Balance Sheet Information at September 30, 2013
		Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
					Companies			Guarantor													Companies			Companies
								Companies										(In thousands)
		(In thousands)															Current assets:
	Current assets:																Cash and cash equivalents	$	25,617		$	(24	)	$	20		$	—		$	25,613
	Cash and cash equivalents	$	4,670		$	(10	)	$	27		$	—		$	4,687		Accounts receivable, net		169,304			2,735			565			—			172,604
	Accounts receivable, net		166,283			2,038			642			—			168,963		Receivable due from ESOP Trust		930			—			—			—			930
	Prepaid expenses and other current assets		5,587			36			25			—			5,648		Prepaid expenses and other current assets		4,449			188			(154	)		—			4,483
	Total current assets		176,540			2,064			694			—			179,298		Total current assets		200,300			2,899			431			—			203,630
	Property, plant and equipment, net		8,552			515			3			—			9,070		Property, plant and equipment, net		9,139			525			4			—			9,668
	Intangible assets, net		1,735			—			—			—			1,735		Intangible assets, net		2,040			—			—			—			2,040
	Goodwill		398,921			—			—			—			398,921		Goodwill		398,921			—			—			—			398,921
	Investment in subsidiaries		28,710			—			—			(28,710	)		—		Investment in subsidiaries		28,420			—			—			(28,420	)		—
	Intercompany receivables		1,963			28,536			—			(30,499	)		—		Intercompany receivables		1,906			27,828			—			(29,734	)		—
	Other assets		10,364			—			4			—			10,368		Other assets		10,363			—			4			—			10,367
	Total assets	$	626,785		$	31,115		$	701		$	(59,209	)	$	599,392		Total assets	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
	Current liabilities:																Current liabilities:
	Interest payable	$	15,590		$	—		$	—		$	—		$	15,590		Interest payable	$	17,758		$	—		$	—		$	—		$	17,758
	Secured notes		326,313			—			—			—			326,313		Trade accounts payable		61,563			58			1			—			61,622
	Trade accounts payable		59,465			40			31			—			59,536		Accrued liabilities		39,169			144			80			—			39,393
	Accrued liabilities		36,710			96			103			—			36,909		Accrued payroll and related liabilities		37,404			517			33			—			37,954
	Accrued payroll and related liabilities		31,399			303			31			—			31,733		Billings in excess of costs revenue earned		4,250			84			—			—			4,334
	Billings in excess of revenue earned		4,452			110			—			—			4,562
																	Total current liabilities		160,144			803			114			—			161,061
	Total current liabilities		473,929			549			165			—			474,643		Intercompany payables		27,826			153			1,754			(29,733	)		—
	Intercompany payables		28,537			—			1,962			(30,499	)		—		Secured Notes		322,286			—			—			—			322,286
	Unsecured notes		234,038			—			—			—			234,038		Unsecured Notes		233,832			—			—			—			233,832
	Accrued compensation and benefits, excluding current portion		5,998			—			—			—			5,998		Accrued compensation and benefits, excluding current portion		5,736			—			—			—			5,736
	Non-current portion of lease obligations		12,110			430			—			—			12,540		Non-current portion of lease obligations		12,374			447			—			—			12,821
	Deferred income taxes		59,873			—			—			—			59,873		Deferred income taxes		58,130			—			—			—			58,130
	Commitments and contingencies																Commitments and contingencies		—			—			—			—			—
	Redeemable common stock		61,896			—			—			—			61,896		Redeemable common stock		61,895			—			—			—			61,895
	Common stock warrants		20,785			—			—			—			20,785		Common stock warrants		20,785			—			—			—			20,785
	Common stock of subsidiaries		—			4,084			9			(4,093	)		—		Common stock of subsidiaries		—			4,084			9			(4,093	)		—
	Accumulated other comprehensive loss		130			—			—			—			130		Accumulated other comprehensive loss		130			—			—			—			130
	Accumulated deficit		(270,511	)		26,052			(1,435	)		(24,617	)		(270,511	)	Accumulated surplus (deficit)		(252,049	)		25,765			(1,438	)		(24,328	)		(252,050	)
	Total liabilities, redeemable common stock and accumulated deficit	$	626,785		$	31,115		$	701		$	(59,209	)	$	599,392		Total liabilities, redeemable common stock and stockholder’s deficit	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
	Condensed Consolidating Balance Sheet as of September 30, 2013 (unaudited)																Condensed Consolidating Balance Sheet Information at September 30, 2012
		Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
								Guarantor													Companies			Companies
								Companies										(In thousands)
		(In thousands)															Current assets:
	Current assets:																Cash and cash equivalents	$	27,271		$	(44	)	$	—		$	—		$	27,227
	Cash and cash equivalents	$	25,617		$	(24	)	$	20		$	—		$	25,613		Accounts receivable, net		172,365			2,783			145			—			175,293
	Accounts receivable, net		169,304			2,735			565			—			172,604		Receivable due from ESOP Trust		1,129			—			—			—			1,129
	Receivable due from ESOP Trust		930			—			—			—			930		Prepaid expenses and other current assets		5,378			70			—			—			5,448
	Prepaid expenses and other current assets		4,449			188			(154	)		—			4,483
																	Total current assets		206,143			2,809			145			—			209,097
	Total current assets		200,300			2,899			431			—			203,630		Property, plant and equipment, net		10,064			529			12			—			10,605
	Property, plant and equipment, net		9,139			525			4			—			9,668		Intangible assets, net		5,242			—			—			—			5,242
	Intangible assets, net		2,040			—			—			—			2,040		Goodwill		398,921			—			—			—			398,921
	Goodwill		398,921			—			—			—			398,921		Investment in subsidiaries		27,994			—			—			(27,994	)		—
	Investment in subsidiaries		28,420			—			—			(28,420	)		—		Intercompany receivables		1,438			27,475			—			(28,913	)		—
	Intercompany receivables		1,906			27,828			—			(29,734	)		—		Other assets		11,427			—			4			—			11,431
	Other assets		10,363			—			4			—			10,367
																	Total assets	$	661,229		$	30,813		$	161		$	(56,907	)	$	635,296
	Total assets	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
																	Current liabilities:
	Current liabilities:																Interest payable	$	17,658		$	—		$	—		$	—		$	17,658
	Interest payable	$	17,758		$	—		$	—		$	—		$	17,758		Trade accounts payable		44,582			201			10			—			44,793
	Trade accounts payable		61,563			58			1			—			61,622		Accrued liabilities		52,265			190			5			—			52,460
	Accrued liabilities		39,169			144			80			—			39,393		Accrued payroll and related liabilities		39,305			589			32			—			39,926
Accrued payroll and related liabilities		37,404			517			33			—			37,954		Billings in excess of costs revenue earned		2,656			6			4			—			2,666
Billings in excess of costs revenue earned		4,250			84			—			—			4,334
																Total current liabilities		156,466			986			51			—			157,503
Total current liabilities		160,144			803			114			—			161,061		Intercompany payables		27,476			—			1,437			(28,913	)		—
Intercompany payables		27,826			153			1,754			(29,733	)		—		Secured Notes		306,502			—			—			—			306,502
Secured Notes		322,286			—			—			—			322,286		Unsecured Notes		242,923			—			—			—			242,923
Unsecured Notes		233,832			—			—			—			233,832		Accrued compensation and benefits, excluding current portion		5,905			—			—			—			5,905
Accrued compensation and benefits, excluding current portion		5,736			—			—			—			5,736		Non-current portion of lease obligations		11,858			506			—			—			12,364
Non-current portion of lease obligations		12,374			447			—			—			12,821		Deferred income taxes		51,156			—			—			—			51,156
Deferred income taxes		58,130			—			—			—			58,130		Commitments and contingencies
Redeemable common stock		61,895			—			—			—			61,895		Redeemable common stock		110,740			—			—			—			110,740
Common stock of subsidiaries		—			4,084			9			(4,093	)		—		Common stock warrants		20,785			—			—			—			20,785
Commitments and contingencies																Common stock of subsidiaries		—			4,084			—			(4,084	)		—
Common stock warrants		20,785			—			—			—			20,785		Accumulated other comprehensive loss		(149	)		—			—			—			(149	)
Accumulated other comprehensive loss		130			—			—			—			130		Accumulated surplus (deficit)		(272,433	)		25,237			(1,327	)		(23,910	)		(272,433	)
Accumulated surplus (deficit)		(252,049	)		25,765			(1,438	)		(24,328	)		(252,050	)
																Total liabilities, redeemable common stock and stockholder’s deficit	$	661,229		$	30,813		$	161		$	(56,907	)	$	635,296
Total liabilities, redeemable common stock and accumulated deficit	$	651,089		$	31,252		$	439		$	(58,154	)	$	624,626
Condensed Consolidating Statement of Comprehensive Loss	'																'
	Condensed Consolidating Statement of Operations and Comprehensive Loss for the Three Months Ended December 31, 2013 (unaudited)																Condensed Consolidating Statement of Comprehensive Loss
		Parent			Guarantor			Non-			Eliminations			Consolidated				Year Ended September 30, 2013
					Companies			Guarantor										Parent			Guarantor			Non-Guarantor			Eliminations			Consolidated
								Companies													Companies			Companies
		(In thousands)																(In thousands)
	Contract revenue	$	183,384			1,771			225			—		$	185,380		Contract revenue	$	839,608		$	8,627		$	737		$	—		$	848,972
	Direct contract expense		144,060			1,091			124			—			145,275		Direct contract expenses		663,380			5,638			486			—			669,504
	Gross profit		39,324			680			101			—			40,105		Gross profit		176,228			2,989			251			—			179,468
	Operating expenses		18,385			392			87						18,864		Operating expenses		81,838			1,972			318			—			84,128
	General and administrative		18,983			1			9			—			18,993		General and administrative		52,491			604			44			—			53,139
	Operating income		1,956			287			5			—			2,248		Operating income (loss)		41,899			413			(111	)		—			42,201
	Other income (expense):																Other income (expense):
	Interest income		11			—			—			—			11		Interest income		55			—			—			—			55
	Interest expense		(18,948	)		—			—			—			(18,948	)	Interest expense		(75,700	)		—			—			—			(75,700	)
	Other		(28	)					—			—			(28	)	Other		(200	)		116			—			—			(84	)
	Equity in net income (loss) of subsidiaries		292						—			(292	)		—		Gain on debt extinguishment		3,913			—			—			—			3,913
																	Equity in net income (loss) of subsidiaries		418			—			—			(418	)		—
	Total other expenses		(18,673	)		—			—			(292	)		(18,965	)
																	Total other income (expense)		(71,514	)		116			—			(418	)		(71,816	)
	(Loss) income before taxes		(16,717	)		287			5			(292	)		(16,717	)	Income (loss) before taxes		(29,615	)		529			(111	)		(418	)		(29,615	)
	Income tax expense		(1,745	)		—			—			—			(1,745	)	Income tax expense		(6,977	)		—			—			—			(6,977	)
	Net loss	$	(18,462	)	$	287		$	5		$	(292	)	$	(18,462	)	Net income (loss)	$	(36,592	)	$	529		$	(111	)	$	(418	)	$	(36,592	)
	Other comprehensive income																Other comprehensive income:
	Postretirement actuarial gains		—			—			—			—			—		Postretirement actuarial gains		279			—			—			—			279
	Comprehensive income (loss)	$	(18,462	)	$	287		$	5		$	(292	)	$	(18,462	)	Comprehensive income (loss)	$	(36,313	)		529			(111	)		(418	)		(36,313	)
																	Condensed Consolidating Statement of Comprehensive Loss
	Condensed Consolidating Statement of Operations and Comprehensive Loss for the Three Months Ended December 31, 2012 (unaudited)
																		Year Ended September 30, 2012
		Parent			Guarantor			Non-			Eliminations			Consolidated				Parent			Guarantor			Non-			Eliminations			Consolidated
					Companies			Guarantor													Companies			Guarantor
								Companies																Companies
		(In thousands)																(In thousands)
	Contract revenue	$	202,057		$	2,218		$	54		$	—		$	204,329		Contract revenue	$	802,664		$	14,015		$	525		$	—		$	817,204
	Direct contract expense		159,162			1,337			136			—			160,635		Direct contract expenses		624,788			7,743			300			—			632,831
	Gross profit		42,895			881			(82	)		—			43,694		Gross profit		177,876			6,272			225			—			184,373
	Operating expenses		21,621			560			69			—			22,250		Operating expenses		88,736			2,531			227			—			91,494
	General and administrative		11,734			49			21			—			11,804		General and administrative		52,123			156			162			—			52,441
	Operating income (loss)		9,540			272			(172	)		—			9,640		Operating income (loss)		37,017			3,585			(164	)		—			40,438
	Other income (expense):																Other income (expense):
	Interest income		17			—			—			—			17		Interest income		78			—			—			—			78
	Interest expense		(18,919	)		—			—			—			(18,919	)	Interest expense		(74,934	)		—			—			—			(74,934	)
	Other		(15	)		—			—			—			(15	)	Other		(63	)		9			(1	)		—			(55	)
	Equity in net income of subsidiaries		100			—			—			(100	)		—		Equity in net income (loss) of subsidiaries		3,429			—			—			(3,429	)		—
	Total other (expense) income		(18,817	)		—			—			(100	)		(18,917	)	Total other income (expense)		(71,490	)		9			(1	)		(3,429	)		(74,911	)
																	Income (loss) before taxes		(34,473	)		3,594			(165	)		(3,429	)		(34,473	)
	(Loss) income before taxes		(9,277	)		272			(172	)		(100	)		(9,277	)	Income tax expense		(6,974	)		—			—			—			(6,974	)
	Income tax expense		(1,744	)		—			—			—			(1,744	)
																	Net income (loss)	$	(41,447	)	$	3,594		$	(165	)	$	(3,429	)	$	(41,447	)
	Net income (loss)	$	(11,021	)	$	272		$	(172	)	$	(100	)	$	(11,021	)
																	Other comprehensive income:
	Other comprehensive income:																Postretirement actuarial gains		26			—			—			—			26
	Postretirement actuarial gains		—			—			—			—			—
																	Comprehensive income (loss)	$	(41,421	)		3,594			(165	)		(3,429	)		(41,421	)
	Comprehensive income (loss)	$	(11,021	)	$	272		$	(172	)	$	(100	)	$	(11,021	)
																	Condensed Consolidating Statement of Comprehensive Loss
																		Year Ended September 30, 2011
																		Parent			Guarantor			Non-			Eliminations			Consolidated
																					Companies			Guarantor
																								Companies
																		(In thousands)
																	Contract revenue	$	769,467		$	17,025		$	822		$	—		$	787,314
																	Direct contract expenses		593,600			9,333			548			—			603,481
																	Gross profit		175,867			7,692			274			—			183,833
																Operating expenses		79,871			3,076			88			—			83,035
																General and administrative		64,374			620			311			—			65,305
																Operating income (loss)		31,622			3,996			(125	)		—			35,493
																Other income (expense):
																Interest income		45			—			—			—			45
																Interest expense		(73,919	)		—			—			—			(73,919	)
																Other		(535	)		568			(1	)		—			32
																Gain on debt extinguishment		939			—			—			—			939
																Equity in net income (loss) of subsidiaries		4,438			—			—			(4,438	)		—
																Total other income (expense)		(69,032	)		568			(1	)		(4,438	)		(72,903	)
																Income (loss) before taxes		(37,410	)		4,564			(126	)		(4,438	)		(37,410	)
																Income tax expense		(6,974	)		—			—			—			(6,974	)
																Net income (loss)	$	(44,384	)	$	4,564		$	(126	)	$	(4,438	)	$	(44,384	)
																Other comprehensive income:
																Post retirement actuarial gains		55			—			—			—			55
																Comprehensive income (loss)		(44,329	)		4,564			(126	)		(4,438	)		(44,329	)
Condensed Consolidating Statement of Cash Flows	'																'
	Condensed Consolidating Statement of Cash Flows for the Three Months Ended December 31, 2013 (unaudited)																Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2013
		Parent			Guarantor			Non-			Consolidated
					Companies			Guarantor										Parent			Guarantors			Non-			Consolidated
								Companies																Guarantors
		(In thousands)																(In thousands)
	Net cash (used in) provided by operating activities	$	(19,934	)	$	24		$	7		$	(19,903	)				Net cash provided by operating activities	$	10,666		$	97		$	20		$	10,783
																	Cash flows from investing activities:
	Cash flows from investing activities:																Capital expenditures		(1,792	)		(77	)		—			(1,869	)
	Capital expenditures		(263	)		(10	)		—			(273	)
																	Net cash provided by (used in) investing activities		(1,792	)		(77	)		—			(1,869	)
	Net cash used in investing activities		(263	)		(10	)		—			(273	)				Cash flows from financing activities:
	Cash flows from financing activities:																Repurchase of Unsecured Notes		(6,030	)		—			—			(6,030	)
	Payment of debt issue costs		(750	)		—			—			(750	)				Revolver borrowings		16,461			—			—			16,461
	Revolver borrowings		10,000			—			—			10,000					Revolver repayments		(16,461	)		—			—			(16,461	)
	Revolver payments		(10,000	)		—			—			(10,000	)				Loan to ESOP Trust		(1,907	)		—			—			(1,907	)
	Redeemable common stock purchased from ESOP Trust		(934	)		—			—			(934	)				ESOP loan repayment		1,907			—			—			1,907
	Redeemable common stock sold to ESOP Trust		934			—			—			934					Redeemable common stock purchased from ESOP Trust		(6,664	)		—			—			(6,664	)
																	Redeemable common stock sold to ESOP Trust		2,166			—			—			2,166
	Net cash used in financing activities		(750	)		—			—			(750	)
	Net (decrease) increase in cash and cash equivalents		(20,947	)		14			7			(20,926	)				Net cash used in financing activities		(10,528	)		—			—			(10,528	)
	Cash and cash equivalents at beginning of period		25,617			(24	)		20			25,613
																	Net increase (decrease) in cash and cash equivalents		(1,654	)		20			20			(1,614	)
	Cash and cash equivalents at end of period	$	4,670		$	(10	)	$	27		$	4,687					Cash and cash equivalents at beginning of period		27,271			(44	)		—			27,227
																	Cash and cash equivalents at end of period	$	25,617		$	(24	)	$	20		$	25,613
	Condensed Consolidating Statement of Cash Flows for the Three Months Ended December 31, 2012 (unaudited)
																	Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2012
		Parent			Guarantor			Non-			Consolidated
					Companies			Guarantor
								Companies										Parent			Guarantors			Non-			Consolidated
		(In thousands)																						Guarantors
	Net cash (used in) provided by operating activities	$	(6,337	)	$	15		$	5		$	(6,317	)					(In thousands)
																	Net cash provided by (used in) operating activities	$	12,700		$	(19	)	$	—		$	12,681
	Cash flows from investing activities:																Cash flows from investing activities:
	Capital expenditures		(603	)		—			—			(603	)				Capital expenditures		(2,733	)		2			—			(2,731	)
	Net cash used in investing activities		(603	)		—			—			(603	)				Net cash provided by (used in) investing activities		(2,733	)		2			—			(2,731	)
	Cash flows from financing activities:
	Redeemable common stock purchased from ESOP Trust		(1,975	)		—			—			(1,975	)				Cash flows from financing activities:
																	Revolver borrowings		26,000			—			—			26,000
	Net cash provided by financing activities		(846	)		—			—			(846	)				Revolver repayments		(26,000	)		—			—			(26,000	)
	Net increase (decrease) in cash and cash equivalents		(7,786	)		15			5			(7,766	)				Loan to ESOP Trust		(477	)		—			—			(477	)
	Cash and cash equivalents at beginning of period		27,271			(44	)		—			27,227					ESOP loan repayment		477			—			—			477
																	Redeemable common stock purchased from ESOP Trust		(4,843	)		—			—			(4,843	)
	Cash and cash equivalents at end of period	$	19,485		$	(29	)	$	5		$	19,461					Redeemable common stock sold to ESOP Trust		1,302			—			—			1,302
																	Net cash used in financing activities		(3,541	)		—			—			(3,541	)
																	Net increase (decrease) in cash and cash equivalents		6,426			(17	)		—			6,409
																	Cash and cash equivalents at beginning of period		20,845			(27	)		—			20,818
																	Cash and cash equivalents at end of period	$	27,271		$	(44	)	$	—		$	27,227
																	Condensed Consolidating Statement of Cash Flows
																	Year Ended September 30, 2011
																		Parent			Guarantors			Non-			Consolidated
																								Guarantors
																		(In thousands)
																	Net cash provided by operating activities	$	5,061		$	636		$	24		$	5,721
																	Cash flows from investing activities:
																	Capital expenditures		(5,694	)		(588	)		(23	)		(6,305	)
																	Proceeds from sale of fixed assets		14			—			—			14
																	Net cash used in investing activities		(5,680	)		(588	)		(23	)		(6,291	)
																	Cash flows from financing activities:
																	Payment of debt issuance cost		(710	)		—			—			(710	)
																	Repurchase unsecured notes		(3,993	)		—			—			(3,993	)
																	Revolver borrowings		17,000			—			—			17,000
																Revolver payments		(17,000	)		—			—			(17,000	)
																Loan to ESOP Trust		(776	)		—			—			(776	)
																ESOP loan repayment		776			—			—			776
																Redeemable common stock purchased from ESOP Trust		(5,762	)		—			—			(5,762	)
																Redeemable common stock sold to ESOP Trust		5,158			—			—			5,158
																Net cash used in financing activities		(5,307	)		—			—			(5,307	)
																Net increase (decrease) in cash and cash equivalents		(5,926	)		48			1			(5,877	)
																Cash and cash equivalents at beginning of period		26,770			(74	)		(1	)		26,695
																Cash and cash equivalents at end of period	$	20,844		$	(26	)	$	—		$	20,818

Interim_Period_Tables

Interim Period (Tables)	12 Months Ended
	Sep. 30, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Interim Period	'
	Interim Period (Unaudited, in thousands except per share information)
		2013 Quarters
		1st			2nd			3rd			4th
	Revenue	$	204,329		$	221,281		$	220,947		$	202,415
	Gross profit	$	43,694		$	46,319		$	46,633		$	42,822
	Net loss	$	(11,021	)	$	(9,131	)	$	(7,087	)	$	(9,353	)
	Net loss per share	$	(1.64	)	$	(1.39	)	$	(1.01	)	$	(1.37	)
	Current assets	$	203,722		$	223,550		$	211,464		$	203,630
	Current liabilities	$	157,168		$	171,700		$	167,253		$	161,061
		2012 Quarters
		1st			2nd			3rd			4th
	Revenue	$	189,891		$	197,112		$	211,514		$	218,687
	Gross profit	$	43,547		$	46,681		$	46,472		$	47,673
	Net loss	$	(12,810	)	$	(10,245	)	$	(8,866	)	$	(9,526	)
	Net loss per share	$	(2.12	)	$	(1.73	)	$	(1.39	)	$	(1.52	)
	Current assets	$	205,819		$	200,703		$	211,266		$	209,097
	Current liabilities	$	166,226		$	152,200		$	166,520		$	157,503

Description_and_Formation_of_t3

Description and Formation of the Business - Additional Information (Detail) (USD $)	Dec. 20, 2002
In Millions, unless otherwise specified
Business Combinations [Abstract]	'
Acquisition cost	$127.30

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
	Contract	Segment
	Reporting_Unit	Reporting_Unit
	Segment	Contract
Property, Plant and Equipment [Line Items]	'	'	'
Number of contracts	3	3	'
Maturity period of cash and cash equivalents	'3 months	'3 months	'
Number of segments	1	1	'
Number of reporting units	2	2	'
Intangible assets, net	$1,735,000	$2,040,000	$5,242,000
Intangible assets, amortization period	'	'1 year 7 months 6 days	'
Accumulated deficit	67,500,000	67,500,000	'
Redeemable common stock	$61,896,000	$61,895,000	$110,740,000
Percentage of receivables due from commercial customers	21.00%	22.00%	'
Secured Notes and Warrants [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Maturity of debt	'2014-11	'2014-11	'
Unsecured Notes [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Maturity of debt	'2015-02	'2015-02	'
Revolving Credit Facility [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Expiration date of agreement	22-Aug-14	22-Aug-14	'
Minimum [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Percentage of income tax benefit	50.00%	50.00%	'
Software [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant and equipment, estimated useful lives	'3 years	'3 years	'
Equipment [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant and equipment, estimated useful lives	'5 years	'5 years	'

Business_Dispositions_Addition

Business Dispositions - Additional information (Detail) (USD $)	1 Months Ended
	Jul. 09, 2010	Sep. 30, 2010
	WCGS Subsidiary [Member]	HFA Subsidiary [Member]
Significant Acquisitions and Disposals [Line Items]	'	'
Sale of assets and liabilities	$5,000,000	'
Gain on sale	5,100,000	'
Sale of subsidiary	'	275,000
Loss on sale	'	($2,400,000)

Employee_Stock_Ownership_Plan_3

Employee Stock Ownership Plan (ESOP) and ESOP Trust - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'
Employee stock ownership plan period of service requirement	'1 year	'1 year
Employee stock ownership plan amendment description	'The Company amended the Plan to eliminate the one year service requirement for employer 401(k) matching contributions; to automatically enroll new hires in the Plan's 401(k) component; and to designate profit sharing contributions exclusively in Alion common stock.	'The Company amended the Plan to eliminate the one year service requirement for employer 401(k) matching contributions; to automatically enroll new hires in the Plan's 401(k) component; and to designate profit sharing contributions exclusively in Alion common stock.

Loss_Per_Share_Additional_Info1

Loss Per Share - Additional Information (Detail)	0 Months Ended	1 Months Ended
	Mar. 22, 2010	Mar. 22, 2010	Mar. 31, 2010
	Unit	Unit	Unit
Earnings Per Share [Line Items]	'	'	'
Common stock purchased	602,614	602,614	'
Exercise price of warrants	0.01	0.01	'
Expiry date	15-Mar-17	15-Mar-17	'
Secured Notes and Warrants [Member]	'	'	'
Earnings Per Share [Line Items]	'	'	'
Secured notes and warrants issued	310,000	310,000	310,000

Redeemable_Common_Stock_Additi1

Redeemable Common Stock - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2013	Mar. 31, 2013
	Age	Age	ESOP [Member]	ESOP [Member]	ESOP [Member]
Common Equity [Line Items]	'	'	'	'	'
Distribution period of the fair value of vested ESOP	'5 years	'5 years	'	'	'
Age of participant's retirement	65	65	'	'	'
Period of delay in ESOP plan balance distribution	'6 years	'6 years	'	'	'
Subsequent distribution period of the fair value of vested ESOP	'5 years	'5 years	'	'	'
Estimated fair value share price	'	'	$8.10	$8.10	$16.25
Estimated aggregate repurchase obligations for the next five years	'	'	'	$14	'
Sale price of common stock	'	$10	'	'	'

Accounts_Receivable_Accounts_R1

Accounts Receivable - Accounts Receivable (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Receivables [Abstract]	'	'	'
Billed receivables and amounts billable as of the balance sheet date	$104,581	$102,211	$94,028
Unbilled receivables:	'	'	'
Amounts billable after the balance sheet date	28,107	36,693	48,730
Revenues recorded in excess of milestone billings on fixed price contracts	3,825	3,289	2,666
Revenues recorded in excess of estimated contract value or funding	17,803	14,605	18,998
Retainages and other amounts billable upon contract completion	18,635	19,557	15,016
Allowance for doubtful accounts	-3,988	-3,751	-4,145
Total Accounts Receivable	$168,963	$172,604	$175,293

Accounts_Receivable_Additional1

Accounts Receivable - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Receivables [Abstract]	'	'	'
Contract receivables	$135.80	$137.50	$138.90
Percentage of contract receivables	79.00%	78.00%	77.00%
Revenue in excess of billings on uncompleted contracts	68.4	74.1	85.4
Revenue from customer-requested work	17.8	14.6	19
Threshold of contractual operating cycles	'1 year	'1 year	'
Exception of invoice and collect unbilled receivables	$18.60	$19.60	'

Property_Plant_and_Equipment_P1

Property, Plant and Equipment - Property, Plant and Equipment (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Property Plant And Equipment [Abstract]	'	'	'
Leasehold improvements	$12,603	$12,984	$12,168
Equipment and software	35,314	35,203	35,562
Total cost	47,917	48,187	47,730
Less: accumulated depreciation and amortization	-38,847	-38,519	-37,125
Net Property, Plant and Equipment	$9,070	$9,668	$10,605

Property_Plant_and_Equipment_A1

Property, Plant and Equipment - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Property Plant And Equipment [Abstract]	'	'	'	'	'
Depreciation and leasehold amortization expense for fixed assets	$778	$788	$3,300	$4,300	$4,400

Goodwill_Additional_Informatio1

Goodwill - Additional Information (Detail) (USD $)	3 Months Ended			6 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
	Segment				Segment
					Reporting_Unit
Goodwill [Line Items]	'	'	'	'	'	'	'
Goodwill	$398,921,000	$398,921,000	'	$398,921,000	$398,921,000	$398,921,000	'
Changes to goodwill during period	'	'	'	'	0	0	0
Number of segments	1	'	'	'	1	'	'
Reduced number of reporting units	'	'	'	'	2	'	'
Contract revenue	185,380,000	'	204,329,000	'	848,972,000	817,204,000	787,314,000
Contract backlog	'	'	'	'	'Contract backlog was approximately 2.6 times trailing twelve month revenue	'Contract backlog was approximately 2.9 times trailing twelve month revenue	'
Projected revenue and EBITDA and discounted median market multiples	'	'	'	'	30.00%	'	'
Weighted average cost of capital rate	'	'	'	'	13.00%	12.50%	'
Hypothetical increase or decrease in the weighted average cost of capital rate	'	'	'	'	10.00%	'	'
Decrease in estimated enterprise value	'	'	'	'	5.70%	'	'
Increase in estimated enterprise value	'	'	'	'	6.90%	'	'
Percentage of value based on EBITDA multiples from mergers and acquisitions to discounted cash flow enterprise value	'	'	'	'	26.00%	'	'
Additional customer contract funding	'	'	'	840,000,000	840,000,000	'	'
Goodwill impairment	0	0	'	'	0	'	'
Estimated fair value of outstanding debt increased	'	'	'	'	10.00%	'	'
Percentage of outstanding common stock declined	'	'	'	'	50.00%	'	'
Hypothetical decrease in fair value of goodwill	'	'	'	'	10.00%	'	'
Intersegment Elimination [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Contract revenue	292,000	'	'	'	292,000	703,000	'
Minimum [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Market multiples for trailing twelve month EBITDA	'	'	'	'	7.6	5.6	'
Market multiples for trailing twelve month revenue	'	'	'	'	0.3	0.3	'
Projected revenue and EBITDA and discounted median market multiples	'	'	'	'	'	14.00%	'
Goodwill for impairment near-term growth values	'	'	'	'	0.00%	0.00%	'
Goodwill for impairment longer-term out year forecasts	'	'	'	'	0.00%	0.00%	'
Maximum [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Market multiples for trailing twelve month EBITDA	'	'	'	'	18.2	18.2	'
Market multiples for trailing twelve month revenue	'	'	'	'	3.01	3.02	'
Projected revenue and EBITDA and discounted median market multiples	'	'	'	'	'	40.00%	'
Goodwill for impairment near-term growth values	'	'	'	'	4.00%	1.00%	'
Goodwill for impairment longer-term out year forecasts	'	'	'	'	4.00%	2.00%	'
Estimated discounted future cash flows decreased	'	'	'	'	1.00%	'	'
Median [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Market multiples for trailing twelve month EBITDA	'	'	'	'	13.4	12.8	'
Market multiples for trailing twelve month revenue	'	'	'	'	1.36	1.32	'
TEOSS [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Goodwill	201,900,000	201,900,000	'	201,900,000	201,900,000	'	'
Contract revenue	477,000,000	'	'	'	477,000,000	435,000,000	'
EISS [Member]	'	'	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'	'	'
Goodwill	197,000,000	197,000,000	'	197,000,000	197,000,000	'	'
Contract revenue	$371,000,000	'	'	'	$371,000,000	$386,000,000	'

Intangible_Assets_Intangible_A1

Intangible Assets - Intangible Assets (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'	'
Intangible Assets, Gross	$114,817	$114,817	$114,817
Intangible Assets, Accumulated Amortization	-113,082	-112,777	-109,575
Intangible Assets, Net	1,735	2,040	5,242
Purchased Contracts [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Intangible Assets, Gross	111,635	111,635	111,635
Intangible Assets, Accumulated Amortization	-110,015	-109,795	-106,935
Intangible Assets, Net	1,620	1,840	4,700
Internal Use Software and Engineering Designs [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Intangible Assets, Gross	3,182	3,182	3,182
Intangible Assets, Accumulated Amortization	-3,067	-2,982	-2,640
Intangible Assets, Net	$115	$200	$542

Intangible_Assets_Additional_I1

Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Goodwill And Intangible Assets Disclosure [Abstract]	'	'	'	'	'
Weighted-average amortization period of intangible assets	'18 months	'	'18 months	'	'
Amortization expense	$305,000	$1,500,000	$3,200,000	$6,500,000	$7,000,000

Intangible_Assets_Estimated_Ag1

Intangible Assets - Estimated Aggregate Amortization Expense (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Goodwill And Intangible Assets Disclosure [Abstract]	'	'	'
2014	$737	$1,079	'
2015	141	736	'
2016	51	141	'
2017	33	51	'
2018	'	33	'
Intangible Assets, Net	$1,735	$2,040	$5,242

LongTerm_Debt_Additional_Infor

Long-Term Debt - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Mar. 31, 2010

Mar. 22, 2010

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Mar. 22, 2010

Mar. 22, 2010

Mar. 31, 2010

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2013

Sep. 30, 2013

Jul. 31, 2013

Jun. 30, 2013

Jun. 30, 2011

Nov. 30, 2010

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Feb. 28, 2007

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Letters of Credit [Member]

Letters of Credit [Member]

Period One [Member]

Period Two [Member]

Subsequent Event [Member]

Eurodollar Base Rate [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Secured Notes and Warrants [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

Unsecured Notes [Member]

PIK Interest Notes Issued [Member]

PIK Interest Notes Issued [Member]

Letters of Credit [Member]

Short-Term Swing Line Loans [Member]

Short-Term Swing Line Loans [Member]

Minimum [Member]

Minimum [Member]

Letters of Credit [Member]

Letters of Credit [Member]

Eurodollar Interest Rate [Member]

Eurodollar Interest Rate [Member]

Alternate Base Rate [Member]

Alternate Base Rate [Member]

Unit

Unit

Unit

Maximum [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$35,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Face value of outstanding notes

310,000,000

'

310,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

333,086,000

329,788,000

323,293,000

'

'

'

'

'

'

235,000,000

235,000,000

245,000,000

'

'

'

'

23,100,000

19,800,000

Credit limit, maximum capacity

30,000,000

'

'

'

'

'

'

'

'

'

'

30,000,000

'

'

'

5,000,000

5,000,000

'

'

35,000,000

35,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility

'

'

'

'

'

'

'

4,000,000

4,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate

'

'

'

'

'

'

'

'

'

'

'

'

6.00%

'

'

'

'

8.50%

8.50%

'

'

2.50%

2.50%

3.50%

3.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate spread basis points

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.00%

6.00%

5.00%

5.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate description

'

'

'

'

'

'

'

'

'

'

'

'

'

'The minimum Eurodollar interest rate is 2.5% plus 600 basis points

'The minimum Eurodollar interest rate is 2.5% plus 600 basis points

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility alternate base rate description

'

'

'

'

'

'

'

'

'

'

'

'

'

'The minimum alternate base rate is 3.5% plus 500 basis points

'The minimum alternate base rate is 3.5% plus 500 basis points

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitment fee, basis points

1.75%

'

1.75%

'

'

'

'

'

'

'

'

'

0.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitment fee, amount

125,000

142,000

533,000

559,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility restrictive covenants EBITDA amount

65,500,000

'

'

'

'

'

'

'

'

63,000,000

65,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility restrictive covenants, period

'Through August 22, 2014

'

'

'

'

'

'

'

'

'

'through August 22, 2014

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of loan by syndicate lenders

'

'

'

'

'

'

'

'

'

'

'

'

'

50.00%

50.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital expenditures covenants

'

'

'

'

'

'

'

'

'

'

'

'

'

8,000,000

8,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Incurrence of a civil or criminal liability

5,000,000

'

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net proceeds from an underwritten public offering

'

'

'

'

'

'

'

'

'

'

'

'

'

35,000,000

35,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ownership percentage for control

'

'

'

'

'

'

'

'

'

'

'

'

'

51.00%

51.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding equity interests

'

'

'

'

'

'

'

'

'

'

'

'

'

37.50%

37.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt, private units value

'

'

'

'

'

310,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

250,000,000

'

'

'

'

Number of units issued

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

310,000

310,000

310,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument interest rate stated percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

12.00%

12.00%

12.00%

'

'

'

'

'

'

'

10.25%

10.25%

'

'

10.25%

'

'

'

'

Common shares called by each warrant

'

'

'

'

'

'

1.9439

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.9439

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Each note face value

'

'

'

'

'

'

1,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument cash interest rate percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument paid-in-kind interest rate percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest on overdue principal

13.00%

'

13.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11.25%

11.25%

'

'

'

'

'

'

'

Debt instrument, maturity date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1-Nov-14

1-Nov-14

'

'

'

'

'

'

'

1-Feb-15

1-Feb-15

'

'

'

'

'

'

'

Ratio of trailing twelve month Adjusted EBITDA to trailing twelve month consolidated interest expense, requirement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'Greater than 2.0 to 1.0

'Greater than 2.0 to 1.0

'

'

'

'

'

'

'

'Greater than 2.0 to 1.0

'Greater than 2.0 to 1.0

'

'

'

'

'

'

'

Ratio of trailing twelve month Adjusted EBITDA to trailing twelve month consolidated interest expense, actual

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'0.89 to 1.0

'0.91 to 1.0

'0.93 to 1.0

'

'

'

'

'

'

'0.92 to 1.0

'0.91 to 1.0

'0.93 to 1.0

'

'

'

'

'

'

Our ratio of Adjusted EBITDA

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

67,700,000

69,000,000

69,300,000

'

'

'

'

'

'

69,600,000

69,000,000

69,300,000

'

'

'

'

'

'

Consolidated Interest Expense

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75,700,000

75,700,000

74,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt covenant amount debt pursuant to certain agreements

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

25,000,000

'

'

'

'

'

'

'

360,000,000

360,000,000

'

'

'

'

'

'

'

Debt covenants amount for capital expenditures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

25,000,000

'

'

'

'

'

'

'

25,000,000

25,000,000

'

'

'

'

'

'

'

Debt covenants amount for capital expenditures as percentage of assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.50%

2.50%

'

'

'

'

'

'

'

2.50%

2.50%

'

'

'

'

'

'

'

Debt covenant amount permitted subordinated debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

35,000,000

35,000,000

'

'

'

'

'

'

'

Other debt covenants amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20,000,000

20,000,000

'

'

'

'

'

'

'

35,000,000

35,000,000

'

'

'

'

'

'

'

Debt covenant exemption

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'If Adjusted EBITDA is at least two times Consolidated Interest Expense

'If Adjusted EBITDA is at least two times Consolidated Interest Expense

'

'

'

'

'

'

'

'If Adjusted EBITDA is at least two times Consolidated Interest Expense

'If Adjusted EBITDA is at least two times Consolidated Interest Expense

'

'

'

'

'

'

'

Debt covenant above required threshold exemption

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0

'Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0

'

'

'

'

'

'

'

'Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0, we may make or pay

'Even if Adjusted EBITDA to Consolidated Interest Expense is not greater than 2.0 to 1.0, we may make or pay

'

'

'

'

'

'

'

Long-term incentive plan payments annual cap

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,000,000

3,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Acquisition or retirement for value debt covenants amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,000,000

10,000,000

'

'

Other payments covenant amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,000,000

10,000,000

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

Debt default acceleration limit for other debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

Judgment for payment against company or any material subsidiary

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

30,000,000

30,000,000

'

'

'

'

'

'

'

Period of judgment for payment against company or any material subsidiary

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'60 days

'60 days

'

'

'

'

'

'

'

'60 days

'60 days

'

'

'

'

'

'

'

Unsecured debt redemption price as percentage of principal in case of change in control

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

101.00%

101.00%

'

'

'

'

'

'

'

101.00%

101.00%

'

'

'

'

'

'

'

Minimum voting power required for change in control purpose

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

35.00%

35.00%

'

'

'

'

'

'

'

35.00%

35.00%

'

'

'

'

'

'

'

Debt instrument redemption occasion

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'From April 1, 2013 through September 30, 2013

'From April 1, 2013 through September 30, 2013

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument redemption price percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

105.00%

105.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument redemption price percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

103.00%

103.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument repurchase amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

15,000,000

15,000,000

'

'

'

'

'

'

'

Debt instrument repurchase amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,000,000

5,000,000

3,000,000

2,000,000

'

'

'

'

'

'

'

'

'

Gains (Losses) on Extinguishment of Debt

'

'

3,913,000

'

939,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,900,000

0

939,000

'

'

'

'

'

Minimum Adjusted EBITDA to consolidated interest expense ratio to maintain under covenants

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

2

'

'

'

'

'

'

'

Adjusted EBITDA to Consolidated Interest Expense ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.92

0.91

'

'

'

'

'

'

'

0.92

0.91

0.93

'

'

'

'

'

'

Consolidated Interest Expense

18,948,000

18,919,000

75,700,000

74,934,000

73,919,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75,700,000

75,700,000

74,900,000

'

'

'

'

'

'

Debt covenant amount permitted transactions with ESOP

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

25,000,000

'

'

'

'

'

'

'

Senior notes refinancing cost

$600,000,000

'

$600,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

LongTerm_Debt_Interest_Payable

Long-Term Debt - Interest Payable (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Interest Expense [Line Items]	'	'	'
Interest payable	$15,590	$17,758	$17,658
Secured Notes and Warrants [Member]	'	'	'
Interest Expense [Line Items]	'	'	'
Interest payable	5,551	13,741	13,470
Unsecured Notes [Member]	'	'	'
Interest Expense [Line Items]	'	'	'
Interest payable	$10,039	$4,017	$4,188

LongTerm_Debt_Principal_Repaym

Long-Term Debt - Principal Repayments (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'
Total Principal Payments in Rolling Year One	'	'
Total Principal Payments in Rolling Year Two	574,788	574,788
Total Principal Payments	574,788	574,788
Secured Notes and Warrants [Member]	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'
Total Principal Payments in Rolling Year One	'	'
Total Principal Payments in Rolling Year Two	339,788	339,788
Total Principal Payments	339,788	339,788
Unsecured Notes [Member]	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'
Total Principal Payments in Rolling Year One	'	'
Total Principal Payments in Rolling Year Two	235,000	235,000
Total Principal Payments	$235,000	$235,000

LongTerm_Debt_Principal_Repaym1

Long-Term Debt - Principal Repayments (Parenthetical) (Detail) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2010	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
PIK notes issued and PIK interest accrued	'	'	$322,286,000	$306,502,000
Face value of outstanding notes	'	310,000,000	310,000,000	'
Secured Notes and Warrants [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
Amount originally issued	310,000,000	'	'	'
Increases in Secured Note principal (PIK Interest)	29,800,000	'	'	'
Face value of outstanding notes	'	333,086,000	329,788,000	323,293,000
Unamortized debt issue costs	'	7,883,000	10,250,000	19,483,000
Debt issue costs	'	7,700,000	7,700,000	'
Debt issuance third-party costs	'	13,500,000	13,500,000	'
Warrants not settleable in cash fair value disclosure	'	20,800,000	20,800,000	'
Maturity of debt	'	'2014-11	'2014-11	'
Unsecured Notes [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
Face value of outstanding notes	'	235,000,000	235,000,000	245,000,000
Unamortized debt issue costs	'	962,000	1,168,000	2,077,000
Debt issue costs	'	7,100,000	7,100,000	'
Maturity of debt	'	'2015-02	'2015-02	'
Original Notes [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
Face value of outstanding notes	'	'	310,000,000	'
PIK Notes [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
PIK notes issued and PIK interest accrued	'	23,100,000	19,800,000	'
PIK Interest [Member]	'	'	'	'
Long Term Debt Maturities Repayments Of Principal [Line Items]	'	'	'	'
PIK notes issued and PIK interest accrued	'	$1,100,000	$2,700,000	'

Fair_Value_Measurement_Face_Va1

Fair Value Measurement - Face Value, Net Carrying Value and Fair Value of Secured and Unsecured Notes (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	$310,000,000	$310,000,000	'
Carrying value	234,038,000	233,832,000	242,923,000
Unsecured Notes [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	235,000,000	235,000,000	245,000,000
Face value of notes outstanding and notes to be issued	235,000,000	235,000,000	245,000,000
Less: unamortized debt issue costs	-962,000	-1,168,000	-2,077,000
Carrying value	234,038,000	233,832,000	242,923,000
Unsecured Notes [Member] | Original Notes [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	235,000,000	235,000,000	245,000,000
Secured Notes and Warrants [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	333,086,000	329,788,000	323,293,000
Face value of notes outstanding and notes to be issued	334,197,000	332,536,000	325,985,000
Less: unamortized debt issue costs	-7,883,000	-10,250,000	-19,483,000
Carrying value	'	322,286,000	306,502,000
Secured Notes and Warrants [Member] | Original Notes [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	310,000,000	310,000,000	310,000,000
Secured Notes and Warrants [Member] | PIK Interest Notes Issued [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Face value of original notes outstanding	23,086,000	19,788,000	13,293,000
PIK interest notes to be issued	1,111,000	2,748,000	2,692,000
Fair Value, Inputs, Level 2 [Member] | Unsecured Notes [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Fair value of outstanding notes	165,894,000	151,928,000	141,605,000
Fair Value, Inputs, Level 2 [Member] | Secured Notes and Warrants [Member]	'	'	'
Fair Value Of Other Financial Instrument [Line Items]	'	'	'
Fair value of outstanding notes	$339,681,000	$335,295,000	$303,598,000

Secured_Note_Common_Stock_Warr3

Secured Note Common Stock Warrants - Additional Information (Detail) (USD $)	Mar. 22, 2010	Mar. 22, 2010	Mar. 22, 2010	Dec. 31, 2013	Sep. 30, 2013
		Capital Units [Member]	Capital Units [Member]	Warrant [Member]	Warrant [Member]
		Unit	Unit
Class of Warrant or Right [Line Items]	'	'	'	'	'
Number of units issued	'	310,000	310,000	'	'
Each secured note face value	$1,000	'	'	'	'
Common shares called by each warrant	1.9439	'	'	'	'
Common stock purchased	602,614	'	'	'	'
Exercise price of warrants	0.01	'	'	'	'
Expiry date	15-Mar-17	'	'	15-Mar-17	15-Mar-17
Warrant exercisable date	'	'	'	22-Mar-11	22-Mar-11
Initial fair value of the secured note warrants	'	'	'	$20,800,000	$20,800,000
Estimated fair value share price	'	'	'	$34.50	$34.50

Leases_Future_Minimum_Lease_Pa1

Leases - Future Minimum Lease Payments (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified
Leases [Abstract]	'	'
2014	$25,076	$26,009
2015	21,183	24,875
2016	17,783	21,041
2017	14,931	17,804
2018	6,162	14,931
And thereafter	12,947	19,109
Gross lease payments	117,579	123,769
Less: non-cancelable subtenant receipts	-1,593	-1,711
Net lease payments	$115,986	$122,058

Leases_Composition_of_Total_Re1

Leases - Composition of Total Rent Expense (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Leases [Abstract]	'	'	'	'	'
Minimum rentals	$5,515	$5,301	$21,530	$20,639	$21,992
Less: Sublease rental income	-143	-104	-600	-156	-1,610
Total rent expense, net	$5,372	$5,197	$20,930	$20,483	$20,382

Postretirement_Benefits_Additi

Postretirement Benefits - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
	Age	Age
Compensation And Retirement Disclosure [Abstract]	'	'	'	'
Employee age limit for eligibility	65	65	'	'
Unfunded plan liability	'	$376	'	'
Payment towards plan benefits	'	39	59	48
Participants contribution towards plan	'	$14	$12	$18

ESOP_Expense_Additional_Inform1

ESOP Expense - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended						12 Months Ended
	Jun. 30, 2011	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2013	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2011
							ESOP [Member]	ESOP [Member]	ESOP [Member]	Common Shares Issued for Stock Options [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]	'	'	'	'	'	'	'	'	'	'
ESOP plan scheme	'	'The Company matches the first 3% and one-half of the next 2% of eligible employee salary deferrals by contributing shares of Alion common stock to the ESOP Trust on March 31 and September 30 each year.	'	'The Company matches the first 3% and one-half of the next 2% of eligible employee salary deferrals by contributing shares of Alion common stock to the ESOP Trust on March 31 and September 30 each year.	'	'	'	'	'	'
Percentage of employer contribution as a percentage of employee contribution deferral	'	3.00%	'	3.00%	'	'	'	'	'	'
Percentage of salary	'	2.00%	'	2.00%	'	'	'	'	'	'
Eligible employee compensation in common stock	1.00%	'	'	2.50%	'	'	'	'	'	'
Eligible employee compensation in cash	1.50%	'	'	'	'	'	'	'	'	'
Recognized ESOP expense	'	$3,600,000	$3,400,000	$13,800,000	$13,800,000	$13,200,000	'	'	'	'
Prior year expense	'	'	'	'	'	1,200,000	'	'	'	11,000,000
Employee funds used for purchase of common stock	'	930,000	'	930,000	'	'	'	'	'	'
Estimated fair value of share price	'	'	'	'	'	'	$8.10	$8.10	$16.25	'
Redeemable common stock, issued value	'	'	'	$13,800,000	'	'	'	'	'	'

Long_Term_Incentive_Plan_Addit

Long Term Incentive Plan - Additional Information (Detail) (Long-Term Incentive Compensation Plan [Member], USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Long-Term Incentive Compensation Plan [Member]	'	'	'	'	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'	'	'	'	'
Grant value, minimum	50.00%	'	50.00%	'	'
Grant value, maximum	150.00%	'	150.00%	'	'
Incentive compensation expense	$804	$742	$2,300	$1,400	$2,800

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Sep. 30, 2011

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Phantom Share Units (PSUs) [Member]

Phantom Stock Plan [Member]

Phantom Stock Plan [Member]

Performance Shares [Member]

Performance Shares [Member]

Retention Phantom Stock Plan [Member]

Retention Phantom Stock Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Vested awards

'

'

'

'

'

'Awards vest ratably over four years with payment following the grant date fifth anniversary

'Awards vest ratably over four years with payment following the grant date fifth anniversary

'

'

'

'

'

'

'

'

'

Awards vesting period

'

'

'

'

'

'4 years

'4 years

'

'

'

'

'

'

'

'

'

Expiration period of grants with no intrinsic value

'

'

'

'

'

'5 years

'5 years

'

'

'

'

'

'

'

'

'

Expiration of plan

'

'

'

'

'

'2016-11

'2016-11

'

'

'

'

'

'

'

'

'

Outstanding stock appreciation rights

'

'

'

'

'

587,000

709,000

'

'

'

'

'

'

'

'

'

Weighted average grant date fair value

'

'

'

'

'

$22.52

$24.96

'

'

'

'

'

'

'

'

'

Grants outstanding

'

'

'

'

'

'

'

'

'

'

0

0

0

0

0

0

Compensation expense credits

'

'

'

'

'

'

$219

$90

$146

'

'

'

'

'

'

'

Aggregate SAR Plan liability

'

'

'

'

'

'

26

'

'

'

'

'

'

'

'

'

Recognized compensation expense

$805

$752

$2,065

$1,310

$2,655

'

'

'

'

$4

'

'

'

'

'

'

Income_Taxes_Additional_Inform1

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Deferred Income Tax Assets And Liabilities [Line Items]	'	'	'	'	'
Deferred tax expense	$1,744	$1,744	$6,974	$6,974	$6,974
Current income tax expense recognized	'	'	3	'	'
Deferred tax assets benefit percentage	50.00%	'	50.00%	'	'
Deferred tax assets and related valuation allowance	105,362	'	97,040	78,414	'
Deferred tax liabilities	-59,873	'	-58,130	-51,156	'
Effective tax rate	-10.40%	-18.80%	-23.60%	-20.20%	-18.60%
India [Member]	'	'	'	'	'
Deferred Income Tax Assets And Liabilities [Line Items]	'	'	'	'	'
Current income tax expense recognized	$2	$0	$2	'	'

Income_Taxes_Provision_for_Inc

Income Taxes - Provision for Income Taxes (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Current:	'	'	'	'	'
Foreign	'	'	$3	'	'
Total current provision	'	'	3	'	'
Deferred:	'	'	'	'	'
Federal	'	'	5,740	5,740	5,740
State	'	'	1,234	1,234	1,234
Total deferred provision	1,744	1,744	6,974	6,974	6,974
Total provision for income taxes	$1,745	$1,744	$6,977	$6,974	$6,974

Income_Taxes_Components_of_Sta

Income Taxes - Components of Statutory U.S. Federal Income Tax Rate to Income Before Taxes (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]	'	'	'	'	'
Expected federal income tax (benefit)	'	'	35.00%	35.00%	35.00%
State income taxes (net of federal benefit)	'	'	4.50%	4.50%	4.50%
Nondeductible expenses	'	'	-0.40%	-0.40%	-0.60%
Provision to return true-ups	'	'	-0.10%	-0.80%	-0.20%
Tax credits	'	'	0.30%	0.00%	0.00%
Changes in valuation allowance	'	'	-62.90%	-58.40%	-57.20%
Income tax expense (benefit)	-10.40%	-18.80%	-23.60%	-20.20%	-18.60%
Expected federal income tax (benefit)	'	'	($10,365)	($12,066)	($13,093)
State income taxes (net of federal benefit)	'	'	-1,325	-1,539	-1,666
Nondeductible expenses	'	'	105	146	232
Provision to return true-ups	'	'	15	286	84
Tax credits	'	'	-79	'	'
Changes in valuation allowance	'	'	18,626	20,147	21,417
Total provision for income taxes	$1,745	$1,744	$6,977	$6,974	$6,974

Income_Taxes_Components_of_Def

Income Taxes - Components of Deferred Tax Assets and Deferred Tax Liabilities (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
In Thousands, unless otherwise specified
Deferred tax assets:	'	'	'
Accrued expenses and reserves	'	$9,228	$11,206
Intangible amortization	'	13,185	14,305
Deferred rent	'	3,680	3,398
Deferred wages	'	4,060	3,954
Depreciation and leases	'	4,375	3,226
Carryforwards and tax credits	'	62,487	42,300
Other	'	25	25
Gross deferred tax assets	'	97,040	78,414
Less Valuation	-105,362	-97,040	-78,414
Deferred tax liabilities:	'	'	'
Goodwill	'	-58,130	-51,156
Net deferred tax asset/(liability)	($59,873)	($58,130)	($51,156)

Segment_Information_and_Custom2

Segment Information and Customer Concentration - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Receivables From Major Customers [Line Items]	'	'	'	'	'
Number of segments	1	'	1	'	'
Number of prime contracts	'	'	5	'	'
Consolidated revenue	'	'	50.00%	50.00%	50.00%
Sales [Member] | U.S. Government Prime Contracts [Member]	'	'	'	'	'
Receivables From Major Customers [Line Items]	'	'	'	'	'
Percentage revenue from government prime contracts to total contract revenue	87.00%	89.00%	89.00%	86.00%	84.00%

Segment_Information_and_Custom3

Segment Information and Customer Concentration - Five Prime Contracts Represented Over Fifty Percent of Our Revenue (Detail)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
DoD - Defense Information Systems Agency [Member] | Weapons System Information Analysis Center for the Defense Information Systems Agency [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Consolidated revenue	27.60%	17.10%	8.20%
DoD - Defense Information Systems Agency [Member] | Modeling and Simulation Information Analysis Center for the Defense Information Systems Agency [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Consolidated revenue	2.50%	8.10%	14.10%
DoD - U.S. Navy [Member] | Seaport-E Multiple Award Contract for the Naval Sea Systems Command [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Consolidated revenue	20.70%	20.10%	13.50%
DoD - U.S. Navy [Member] | Naval Sea Systems Command Surface Ships Life Cycle Program Management and Engineering Support [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Consolidated revenue	7.20%	5.80%	'
DoD - U.S. Air Force [Member] | Technical and Analytical Support for the U.S. Air Force [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Consolidated revenue	8.40%	9.90%	11.20%

GuarantorNonguarantor_Condense2

Guarantor/Non-guarantor Condensed Consolidated Financial Statements Additional Information (Detail)	Dec. 31, 2013	Sep. 30, 2013
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]	'	'
Ownership in subsidiary percentage	100.00%	100.00%

Recovered_Sheet1

Guarantor/Non-Guarantor Condensed Consolidated Financial Information - Condensed Consolidating Balance Sheet (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Sep. 30, 2010
In Thousands, unless otherwise specified
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	$4,687	$25,613	'	'	$19,461	$27,227	'	'	'	$20,818	$26,695
Accounts receivable, net	168,963	172,604	'	'	'	175,293	'	'	'	'	'
Receivable due from ESOP Trust	'	930	'	'	'	1,129	'	'	'	'	'
Prepaid expenses and other current assets	5,648	4,483	'	'	'	5,448	'	'	'	'	'
Total current assets	179,298	203,630	211,464	223,550	203,722	209,097	211,266	200,703	205,819	'	'
Property, plant and equipment, net	9,070	9,668	'	'	'	10,605	'	'	'	'	'
Intangible assets, net	1,735	2,040	'	'	'	5,242	'	'	'	'	'
Goodwill	398,921	398,921	'	'	'	398,921	'	'	'	'	'
Other assets	10,368	10,367	'	'	'	11,431	'	'	'	'	'
Total assets	599,392	624,626	'	'	'	635,296	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Interest payable	15,590	17,758	'	'	'	17,658	'	'	'	'	'
Trade accounts payable	59,536	61,622	'	'	'	44,793	'	'	'	'	'
Accrued liabilities	36,909	39,393	'	'	'	52,460	'	'	'	'	'
Accrued payroll and related liabilities	31,733	37,954	'	'	'	39,926	'	'	'	'	'
Billings in excess of costs revenue earned	4,562	4,334	'	'	'	2,666	'	'	'	'	'
Total current liabilities	474,643	161,061	167,253	171,700	157,168	157,503	166,520	152,200	166,226	'	'
Secured Notes	'	322,286	'	'	'	306,502	'	'	'	'	'
Unsecured Notes	234,038	233,832	'	'	'	242,923	'	'	'	'	'
Accrued compensation and benefits, excluding current portion	5,998	5,736	'	'	'	5,905	'	'	'	'	'
Non-current portion of lease obligations	12,540	12,821	'	'	'	12,364	'	'	'	'	'
Deferred income taxes	59,873	58,130	'	'	'	51,156	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Redeemable common stock	61,896	61,895	'	'	'	110,740	'	'	'	'	'
Common stock warrants	20,785	20,785	'	'	'	20,785	'	'	'	'	'
Accumulated other comprehensive loss	130	130	'	'	'	-149	'	'	'	'	'
Accumulated surplus (deficit)	-270,511	-252,050	'	'	'	-272,433	'	'	'	'	'
Total liabilities, redeemable common stock and stockholder's deficit	'	624,626	'	'	'	635,296	'	'	'	'	'
Parent [Member]	'	'	'	'	'	'	'	'	'	'	'
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	4,670	25,617	'	'	19,485	27,271	'	'	'	20,844	26,770
Accounts receivable, net	166,283	169,304	'	'	'	172,365	'	'	'	'	'
Receivable due from ESOP Trust	'	930	'	'	'	1,129	'	'	'	'	'
Prepaid expenses and other current assets	5,587	4,449	'	'	'	5,378	'	'	'	'	'
Total current assets	176,540	200,300	'	'	'	206,143	'	'	'	'	'
Property, plant and equipment, net	8,552	9,139	'	'	'	10,064	'	'	'	'	'
Intangible assets, net	1,735	2,040	'	'	'	5,242	'	'	'	'	'
Goodwill	398,921	398,921	'	'	'	398,921	'	'	'	'	'
Investment in subsidiaries	28,710	28,420	'	'	'	27,994	'	'	'	'	'
Intercompany receivables	1,963	1,906	'	'	'	1,438	'	'	'	'	'
Other assets	10,364	10,363	'	'	'	11,427	'	'	'	'	'
Total assets	626,785	651,089	'	'	'	661,229	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Interest payable	15,590	17,758	'	'	'	17,658	'	'	'	'	'
Trade accounts payable	59,465	61,563	'	'	'	44,582	'	'	'	'	'
Accrued liabilities	36,710	39,169	'	'	'	52,265	'	'	'	'	'
Accrued payroll and related liabilities	31,399	37,404	'	'	'	39,305	'	'	'	'	'
Billings in excess of costs revenue earned	4,452	4,250	'	'	'	2,656	'	'	'	'	'
Total current liabilities	473,929	160,144	'	'	'	156,466	'	'	'	'	'
Intercompany payables	28,537	27,826	'	'	'	27,476	'	'	'	'	'
Secured Notes	'	322,286	'	'	'	306,502	'	'	'	'	'
Unsecured Notes	234,038	233,832	'	'	'	242,923	'	'	'	'	'
Accrued compensation and benefits, excluding current portion	5,998	5,736	'	'	'	5,905	'	'	'	'	'
Non-current portion of lease obligations	12,110	12,374	'	'	'	11,858	'	'	'	'	'
Deferred income taxes	59,873	58,130	'	'	'	51,156	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Redeemable common stock	61,896	61,895	'	'	'	110,740	'	'	'	'	'
Common stock warrants	20,785	20,785	'	'	'	20,785	'	'	'	'	'
Accumulated other comprehensive loss	130	130	'	'	'	-149	'	'	'	'	'
Accumulated surplus (deficit)	-270,511	-252,049	'	'	'	-272,433	'	'	'	'	'
Total liabilities, redeemable common stock and stockholder's deficit	'	651,089	'	'	'	661,229	'	'	'	'	'
Guarantor Companies [Member]	'	'	'	'	'	'	'	'	'	'	'
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	-10	-24	'	'	-29	-44	'	'	'	-26	-74
Accounts receivable, net	2,038	2,735	'	'	'	2,783	'	'	'	'	'
Prepaid expenses and other current assets	36	188	'	'	'	70	'	'	'	'	'
Total current assets	2,064	2,899	'	'	'	2,809	'	'	'	'	'
Property, plant and equipment, net	515	525	'	'	'	529	'	'	'	'	'
Intercompany receivables	28,536	27,828	'	'	'	27,475	'	'	'	'	'
Total assets	31,115	31,252	'	'	'	30,813	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Trade accounts payable	40	58	'	'	'	201	'	'	'	'	'
Accrued liabilities	96	144	'	'	'	190	'	'	'	'	'
Accrued payroll and related liabilities	303	517	'	'	'	589	'	'	'	'	'
Billings in excess of costs revenue earned	110	84	'	'	'	6	'	'	'	'	'
Total current liabilities	549	803	'	'	'	986	'	'	'	'	'
Intercompany payables	'	153	'	'	'	'	'	'	'	'	'
Non-current portion of lease obligations	430	447	'	'	'	506	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Common stock of subsidiaries	4,084	4,084	'	'	'	4,084	'	'	'	'	'
Accumulated surplus (deficit)	26,052	25,765	'	'	'	25,237	'	'	'	'	'
Total liabilities, redeemable common stock and stockholder's deficit	'	31,252	'	'	'	30,813	'	'	'	'	'
Non-Guarantor Companies [Member]	'	'	'	'	'	'	'	'	'	'	'
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	27	20	'	'	5	'	'	'	'	'	-1
Accounts receivable, net	642	565	'	'	'	145	'	'	'	'	'
Prepaid expenses and other current assets	25	-154	'	'	'	'	'	'	'	'	'
Total current assets	694	431	'	'	'	145	'	'	'	'	'
Property, plant and equipment, net	3	4	'	'	'	12	'	'	'	'	'
Other assets	4	4	'	'	'	4	'	'	'	'	'
Total assets	701	439	'	'	'	161	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Trade accounts payable	31	1	'	'	'	10	'	'	'	'	'
Accrued liabilities	103	80	'	'	'	5	'	'	'	'	'
Accrued payroll and related liabilities	31	33	'	'	'	32	'	'	'	'	'
Billings in excess of costs revenue earned	'	'	'	'	'	4	'	'	'	'	'
Total current liabilities	165	114	'	'	'	51	'	'	'	'	'
Intercompany payables	1,962	1,754	'	'	'	1,437	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Common stock of subsidiaries	9	9	'	'	'	'	'	'	'	'	'
Accumulated surplus (deficit)	-1,435	-1,438	'	'	'	-1,327	'	'	'	'	'
Total liabilities, redeemable common stock and stockholder's deficit	'	439	'	'	'	161	'	'	'	'	'
Eliminations [Member]	'	'	'	'	'	'	'	'	'	'	'
Current assets:	'	'	'	'	'	'	'	'	'	'	'
Investment in subsidiaries	-28,710	-28,420	'	'	'	-27,994	'	'	'	'	'
Intercompany receivables	-30,499	-29,734	'	'	'	-28,913	'	'	'	'	'
Total assets	-59,209	-58,154	'	'	'	-56,907	'	'	'	'	'
Current liabilities:	'	'	'	'	'	'	'	'	'	'	'
Intercompany payables	-30,499	-29,733	'	'	'	-28,913	'	'	'	'	'
Commitments and contingencies	'	'	'	'	'	'	'	'	'	'	'
Common stock of subsidiaries	-4,093	-4,093	'	'	'	-4,084	'	'	'	'	'
Accumulated surplus (deficit)	-24,617	-24,328	'	'	'	-23,910	'	'	'	'	'
Total liabilities, redeemable common stock and stockholder's deficit	'	($58,154)	'	'	'	($56,907)	'	'	'	'	'

Recovered_Sheet2

Guarantor/Non-Guarantor Condensed Consolidated Financial Information - Condensed Consolidating Statement of Comprehensive Loss (Detail) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Schedule Of Condensed Consolidating Statement Of Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

$185,380,000

'

'

'

$204,329,000

'

'

'

'

$848,972,000

$817,204,000

$787,314,000

Direct contract expenses

145,275,000

'

'

'

160,635,000

'

'

'

'

669,504,000

632,831,000

603,481,000

Gross profit

40,105,000

42,822,000

46,633,000

46,319,000

43,694,000

47,673,000

46,472,000

46,681,000

43,547,000

179,468,000

184,373,000

183,833,000

Operating expenses

18,864,000

'

'

'

22,250,000

'

'

'

'

84,128,000

91,494,000

83,035,000

General and administrative

18,993,000

'

'

'

11,804,000

'

'

'

'

53,139,000

52,441,000

65,305,000

Operating income (loss)

2,248,000

'

'

'

9,640,000

'

'

'

'

42,201,000

40,438,000

35,493,000

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Interest income

11,000

'

'

'

17,000

'

'

'

'

55,000

78,000

45,000

Interest expense

-18,948,000

'

'

'

-18,919,000

'

'

'

'

-75,700,000

-74,934,000

-73,919,000

Other

-28,000

'

'

'

-15,000

'

'

'

'

-84,000

-55,000

32,000

Gains (losses) on extinguishment of debt

'

'

'

'

'

'

'

'

'

3,913,000

'

939,000

Total other (expense) income

-18,965,000

'

'

'

-18,917,000

'

'

'

'

-71,816,000

-74,911,000

-72,903,000

Income (loss) before taxes

-16,717,000

'

'

'

-9,277,000

'

'

'

'

-29,615,000

-34,473,000

-37,410,000

Income tax expense

-1,745,000

'

'

'

-1,744,000

'

'

'

'

-6,977,000

-6,974,000

-6,974,000

Net income (loss)

-18,462,000

-9,353,000

-7,087,000

-9,131,000

-11,021,000

-9,526,000

-8,866,000

-10,245,000

-12,810,000

-36,592,000

-41,447,000

-44,384,000

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Post retirement actuarial gains

'

'

'

'

'

'

'

'

'

279,000

26,000

55,000

Comprehensive income (loss)

-18,462,000

'

'

'

-11,021,000

'

'

'

'

-36,313,000

-41,421,000

-44,329,000

Parent [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Schedule Of Condensed Consolidating Statement Of Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

183,384,000

'

'

'

202,057,000

'

'

'

'

839,608,000

802,664,000

769,467,000

Direct contract expenses

144,060,000

'

'

'

159,162,000

'

'

'

'

663,380,000

624,788,000

593,600,000

Gross profit

39,324,000

'

'

'

42,895,000

'

'

'

'

176,228,000

177,876,000

175,867,000

Operating expenses

18,385,000

'

'

'

21,621,000

'

'

'

'

81,838,000

88,736,000

79,871,000

General and administrative

18,983,000

'

'

'

11,734,000

'

'

'

'

52,491,000

52,123,000

64,374,000

Operating income (loss)

1,956,000

'

'

'

9,540,000

'

'

'

'

41,899,000

37,017,000

31,622,000

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Interest income

11,000

'

'

'

17,000

'

'

'

'

55,000

78,000

45,000

Interest expense

-18,948,000

'

'

'

-18,919,000

'

'

'

'

-75,700,000

-74,934,000

-73,919,000

Other

-28,000

'

'

'

-15,000

'

'

'

'

-200,000

-63,000

-535,000

Gains (losses) on extinguishment of debt

'

'

'

'

'

'

'

'

'

3,913,000

'

939,000

Equity in net income (loss) of subsidiaries

292,000

'

'

'

100,000

'

'

'

'

418,000

3,429,000

4,438,000

Total other (expense) income

-18,673,000

'

'

'

-18,817,000

'

'

'

'

-71,514,000

-71,490,000

-69,032,000

Income (loss) before taxes

-16,717,000

'

'

'

-9,277,000

'

'

'

'

-29,615,000

-34,473,000

-37,410,000

Income tax expense

-1,745,000

'

'

'

-1,744,000

'

'

'

'

-6,977,000

-6,974,000

-6,974,000

Net income (loss)

-18,462,000

'

'

'

-11,021,000

'

'

'

'

-36,592,000

-41,447,000

-44,384,000

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Post retirement actuarial gains

'

'

'

'

'

'

'

'

'

279,000

26,000

55,000

Comprehensive income (loss)

-18,462,000

'

'

'

-11,021,000

'

'

'

'

-36,313,000

-41,421,000

-44,329,000

Guarantor Companies [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Schedule Of Condensed Consolidating Statement Of Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

1,771,000

'

'

'

2,218,000

'

'

'

'

8,627,000

14,015,000

17,025,000

Direct contract expenses

1,091,000

'

'

'

1,337,000

'

'

'

'

5,638,000

7,743,000

9,333,000

Gross profit

680,000

'

'

'

881,000

'

'

'

'

2,989,000

6,272,000

7,692,000

Operating expenses

392,000

'

'

'

560,000

'

'

'

'

1,972,000

2,531,000

3,076,000

General and administrative

1,000

'

'

'

49,000

'

'

'

'

604,000

156,000

620,000

Operating income (loss)

287,000

'

'

'

272,000

'

'

'

'

413,000

3,585,000

3,996,000

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Other

'

'

'

'

'

'

'

'

'

116,000

9,000

568,000

Total other (expense) income

'

'

'

'

'

'

'

'

'

116,000

9,000

568,000

Income (loss) before taxes

287,000

'

'

'

272,000

'

'

'

'

529,000

3,594,000

4,564,000

Net income (loss)

287,000

'

'

'

272,000

'

'

'

'

529,000

3,594,000

4,564,000

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Post retirement actuarial gains

'

'

'

'

'

'

'

'

'

'

'

'

Comprehensive income (loss)

287,000

'

'

'

272,000

'

'

'

'

529,000

3,594,000

4,564,000

Non-Guarantor Companies [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Schedule Of Condensed Consolidating Statement Of Operations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Contract revenue

225,000

'

'

'

54,000

'

'

'

'

737,000

525,000

822,000

Direct contract expenses

124,000

'

'

'

136,000

'

'

'

'

486,000

300,000

548,000

Gross profit

101,000

'

'

'

-82,000

'

'

'

'

251,000

225,000

274,000

Operating expenses

87,000

'

'

'

69,000

'

'

'

'

318,000

227,000

88,000

General and administrative

9,000

'

'

'

21,000

'

'

'

'

44,000

162,000

311,000

Operating income (loss)

5,000

'

'

'

-172,000

'

'

'

'

-111,000

-164,000

-125,000

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Other

'

'

'

'

'

'

'

'

'

'

-1,000

-1,000

Total other (expense) income

'

'

'

'

'

'

'

'

'

'

-1,000

-1,000

Income (loss) before taxes

5,000

'

'

'

-172,000

'

'

'

'

-111,000

-165,000

-126,000

Net income (loss)

5,000

'

'

'

-172,000

'

'

'

'

-111,000

-165,000

-126,000

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Post retirement actuarial gains

'

'

'

'

'

'

'

'

'

'

'

'

Comprehensive income (loss)

5,000

'

'

'

-172,000

'

'

'

'

-111,000

-165,000

-126,000

Eliminations [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

Equity in net income (loss) of subsidiaries

-292,000

'

'

'

-100,000

'

'

'

'

-418,000

-3,429,000

-4,438,000

Total other (expense) income

-292,000

'

'

'

-100,000

'

'

'

'

-418,000

-3,429,000

-4,438,000

Income (loss) before taxes

-292,000

'

'

'

-100,000

'

'

'

'

-418,000

-3,429,000

-4,438,000

Net income (loss)

-292,000

'

'

'

-100,000

'

'

'

'

-418,000

-3,429,000

-4,438,000

Other comprehensive income:

'

'

'

'

'

'

'

'

'

'

'

'

Post retirement actuarial gains

'

'

'

'

'

'

'

'

'

'

'

'

Comprehensive income (loss)

($292,000)

'

'

'

($100,000)

'

'

'

'

($418,000)

($3,429,000)

($4,438,000)

Recovered_Sheet3

Guarantor/Non-Guarantor Condensed Consolidated Financial Information - Condensed Consolidating Statement of Cash Flows (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'	'	'
Net cash provided by (used in) operating activities	($19,903)	($6,317)	$10,783	$12,681	$5,721
Cash flows from investing activities:	'	'	'	'	'
Capital expenditures	-273	-603	-1,869	-2,731	-6,305
Proceeds from sale of fixed assets	'	'	'	'	14
Net cash provided by (used in) investing activities	-273	-603	-1,869	-2,731	-6,291
Cash flows from financing activities:	'	'	'	'	'
Payment of debt issuance cost	-750	'	'	'	-710
Repurchase of Unsecured Notes	'	'	-6,030	'	-3,993
Revolver borrowings	10,000	'	16,461	26,000	17,000
Revolver payments	-10,000	'	-16,461	-26,000	-17,000
Loan to ESOP Trust	'	'	-1,907	-477	-776
ESOP loan repayment	'	'	1,907	477	776
Redeemable common stock purchased from ESOP Trust	-934	-1,975	-6,664	-4,843	-5,762
Redeemable common stock sold to ESOP Trust	934	1,129	2,166	1,302	5,158
Net cash used in financing activities	-750	-846	-10,528	-3,541	-5,307
Net increase (decrease) in cash and cash equivalents	-20,926	-7,766	-1,614	6,409	-5,877
Cash and cash equivalents at beginning of period	25,613	27,227	27,227	20,818	26,695
Cash and cash equivalents at end of period	4,687	19,461	25,613	27,227	20,818
Parent [Member]	'	'	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'	'	'
Net cash provided by (used in) operating activities	-19,934	-6,337	10,666	12,700	5,061
Cash flows from investing activities:	'	'	'	'	'
Capital expenditures	-263	-603	-1,792	-2,733	-5,694
Proceeds from sale of fixed assets	'	'	'	'	14
Net cash provided by (used in) investing activities	-263	-603	-1,792	-2,733	-5,680
Cash flows from financing activities:	'	'	'	'	'
Payment of debt issuance cost	-750	'	'	'	-710
Repurchase of Unsecured Notes	'	'	-6,030	'	-3,993
Revolver borrowings	10,000	'	16,461	26,000	17,000
Revolver payments	-10,000	'	-16,461	-26,000	-17,000
Loan to ESOP Trust	'	'	-1,907	-477	-776
ESOP loan repayment	'	'	1,907	477	776
Redeemable common stock purchased from ESOP Trust	-934	-1,975	-6,664	-4,843	-5,762
Redeemable common stock sold to ESOP Trust	934	'	2,166	1,302	5,158
Net cash used in financing activities	-750	-846	-10,528	-3,541	-5,307
Net increase (decrease) in cash and cash equivalents	-20,947	-7,786	-1,654	6,426	-5,926
Cash and cash equivalents at beginning of period	25,617	27,271	27,271	20,844	26,770
Cash and cash equivalents at end of period	4,670	19,485	25,617	27,271	20,844
Guarantor Companies [Member]	'	'	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'	'	'
Net cash provided by (used in) operating activities	24	15	97	-19	636
Cash flows from investing activities:	'	'	'	'	'
Capital expenditures	-10	'	-77	2	-588
Net cash provided by (used in) investing activities	-10	'	-77	2	-588
Cash flows from financing activities:	'	'	'	'	'
Net increase (decrease) in cash and cash equivalents	14	15	20	-17	48
Cash and cash equivalents at beginning of period	-24	-44	-44	-26	-74
Cash and cash equivalents at end of period	-10	-29	-24	-44	-26
Non-Guarantor Companies [Member]	'	'	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'	'	'
Net cash provided by (used in) operating activities	7	5	20	'	24
Cash flows from investing activities:	'	'	'	'	'
Capital expenditures	'	'	'	'	-23
Net cash provided by (used in) investing activities	'	'	'	'	-23
Cash flows from financing activities:	'	'	'	'	'
Net increase (decrease) in cash and cash equivalents	7	5	20	'	1
Cash and cash equivalents at beginning of period	20	'	'	'	-1
Cash and cash equivalents at end of period	$27	$5	$20	'	'

Subsequent_Event_Additional_In1

Subsequent Event - Additional Information (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013
			Subsequent Event [Member]
Subsequent Event [Line Items]	'	'	'
Fees paid for waiver	'	'	$0
Employee funds used for purchase of common stock	$930,000	$930,000	$934

Interim_Period_Schedule_of_Int

Interim Period - Schedule of Interim Period (Detail) (USD $)	3 Months Ended									12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Quarterly Financial Information Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	$202,415	$220,947	$221,281	$204,329	$218,687	$211,514	$197,112	$189,891	'	'	'
Gross profit	40,105	42,822	46,633	46,319	43,694	47,673	46,472	46,681	43,547	179,468	184,373	183,833
Net loss	-18,462	-9,353	-7,087	-9,131	-11,021	-9,526	-8,866	-10,245	-12,810	-36,592	-41,447	-44,384
Net loss per share	'	($1.37)	($1.01)	($1.39)	($1.64)	($1.52)	($1.39)	($1.73)	($2.12)	'	'	'
Current assets	179,298	203,630	211,464	223,550	203,722	209,097	211,266	200,703	205,819	203,630	209,097	'
Current liabilities	$474,643	$161,061	$167,253	$171,700	$157,168	$157,503	$166,520	$152,200	$166,226	$161,061	$157,503	'