Stock Based Compensation - Additional Information (Detail) In Thousands, unless otherwise specified	6 Months Ended
Dec. 31, 2013
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance under stock incentive plan	1,400
Shares available for future grant	201
Purchase price as a percentage of the lesser of the market value of such shares at either the beginning or the end of each nine-month offering period	85.00%
Percentage of employee compensation that may be uses to purchase common stock through payroll deductions, maximum	10.00%
2005 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance under stock incentive plan	8,018
Exercise price of stock option, percentage	100.00%
Shares available for future grant	1,095
2005 Stock Incentive Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of stock option	7 years

Employee Stock Purchase Plan, Maximum Percentage of Compensation to Purchase Shares By Eligible Participants

No definition available.

Name:	mrcy_EmployeeStockPurchasePlanMaximumPercentageOfCompensationToPurchaseSharesByEligibleParticipants
Namespace Prefix:	mrcy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum Grant Date Fair Value Of Nonqualified Stock Options As Percentage Of Fair Value Of Common Stock

+ References

No definition available.

+ Details

Name:	mrcy_MinimumGrantDateFairValueOfNonqualifiedStockOptionsAsPercentageOfFairValueOfCommonStock
Namespace Prefix:	mrcy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum number of years for the company's stock options before they expire.

+ References

No definition available.

+ Details

Name:	mrcy_ShareBasedCompensationArrangementByShareBasedPaymentAwardContractualLife
Namespace Prefix:	mrcy_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The discount rate from market value on offering date that participants pay for shares.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant