Summary of Performance of Operations by Reportable Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Revenue Reconciling Item [Line Items]
Intersegment revenues	$ 0	$ 0	$ 0	$ 0
Net revenues	53,090	49,804	107,030	99,232
Adjusted EBITDA	5,092	999	8,711	2,641
Reportable Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues to unaffiliated customers	53,090	49,804	107,030	99,232
Net revenues	53,090	49,804	107,030	99,232
Adjusted EBITDA	5,092	999	8,711	2,641
MCE \| Reportable Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues to unaffiliated customers	42,305	37,251	85,793	69,147
Intersegment revenues	2,733	3,239	3,847	8,147
Net revenues	45,038	40,490	89,640	77,294
Adjusted EBITDA	4,082	(324)	6,425	(2,531)
Mercury Defense and Intelligence Systems \| Reportable Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues to unaffiliated customers	10,603	14,064	21,733	29,892
Intersegment revenues		4	0	12
Net revenues	10,603	14,068	21,733	29,904
Adjusted EBITDA	921	1,973	2,279	5,199
Eliminations \| Reportable Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Net revenues to unaffiliated customers	182	(1,511)	(496)	193
Intersegment revenues	(2,733)	(3,243)	(3,847)	(8,159)
Net revenues	(2,551)	(4,754)	(4,343)	(7,966)
Adjusted EBITDA	$ 89	$ (650)	$ 7	$ (27)

Tabular disclosure of adjusted EBITDA. Adjusted EBITDA is defined as earnings from continuing operations before interest income and expense, income taxes, depreciation, amortization of acquired intangible assets, restructuring, impairment of long-lived assets, acquisition costs and other related expenses, fair value adjustments from purchase accounting and stock-based compensation costs.

No definition available.

+ Details

Name:	mrcy_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization
Namespace Prefix:	mrcy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue from external customers for the reportable segment. Such disclosure is presented if the amount is: (a) included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-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.

+ Details

Name:	us-gaap_RevenuesFromExternalCustomers
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue from transactions with other operating segments of the same entity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-Subparagraph b

-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.

+ Details

Name:	us-gaap_RevenuesFromTransactionsWithOtherOperatingSegmentsOfSameEntity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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