Summary of Significant Accounting Policies - Revenue Recognition (Details) (Multiple Delivery Revenue)	12 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2011
Multiple Delivery Revenue
Deferred Revenue Arrangement [Line Items]
Percentage of revenue under multi- deliverable arrangement	34.00%	39.00%	50.00%

Percentage of total revenue recognized under multiple-deliverable arrangements during the reporting periods.

No definition available.

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