Business Segment And Geographic Area Information (Contracts Exceeding 10% Of Receivables) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Receivables, net	$ 540,468	$ 528,765
Percentage of Receivable, Total	100.00%	100.00%
U S Army Contract A [Member]
Segment Reporting Information [Line Items]
Receivables, net	88,359
Receivables, net		25,357
Percentage of Receivable, Major Contract	16.30%
Percentage of Receivable, Other		4.80%
U S Army Contract B [Member]
Segment Reporting Information [Line Items]
Receivables, net	59,309
Receivables, net		6,778
Percentage of Receivable, Major Contract	11.00%
Percentage of Receivable, Other		1.30%
All Other Contracts Member
Segment Reporting Information [Line Items]
Receivables, net	$ 392,800	$ 496,630
Percentage of Receivable, Other	72.70%	93.90%

Contract From External Customer Exceeding Ten Percent Of Receivables, Net.

No definition available.

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- Definition

Contract From External Customer Exceeding Ten Percent Of Receivables, Net Percentage.

+ References

No definition available.

+ Details

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- Definition

Contract From External Customer Not Exceeding Ten Percent Of Receivables, Net.

+ References

No definition available.

+ Details

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Namespace Prefix:	mant_
Data Type:	xbrli:monetaryItemType
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- Definition

Contract From External Customer Not Exceeding Ten Percent Of Receivables, Net, Percentage.

+ References

No definition available.

+ Details

Name:	mant_ContractFromExternalCustomerNotExceedingTenPercentOfReceivablesNetPercentage
Namespace Prefix:	mant_
Data Type:	num:percentItemType
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- Definition

The percentage of receivables, net.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 4

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph a

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3,4)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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- Details

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