Changes in Carrying Amount of Goodwill (Detail) (USD $) In Thousands, unless otherwise specified														3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2013 Mercury Commercial Electronics	Dec. 31, 2012 Mercury Commercial Electronics	Mar. 31, 2013 Mercury Defense Systems	Dec. 31, 2012 Mercury Defense Systems	Mar. 31, 2013 Mercury Intelligence Systems	Dec. 31, 2012 Mercury Intelligence Systems	Dec. 31, 2012 ACS	Jun. 30, 2012 ACS	Dec. 31, 2012 MFS	Jun. 30, 2012 MFS	Mar. 31, 2013 Micronetics	Dec. 31, 2012 Micronetics	Mar. 31, 2013 Micronetics Mercury Commercial Electronics	Dec. 31, 2012 Micronetics ACS	Dec. 31, 2012 Micronetics MFS	Dec. 31, 2012 KOR Electronics	Dec. 31, 2012 KOR Electronics ACS	Dec. 31, 2012 KOR Electronics MFS
Goodwill [Line Items]
Beginning Balance	$ 178,398	$ 178,429	$ 132,621	$ 135,660	$ 135,691	$ 33,768	$ 33,768	$ 8,970	$ 8,970	$ 159,279	$ 113,471	$ 19,150	$ 19,150
Goodwill Adjustment														(31)		(31)			(701)	(701)
Goodwill															46,509		46,509
Ending Balance	$ 178,398	$ 178,429	$ 132,621	$ 135,660	$ 135,691	$ 33,768	$ 33,768	$ 8,970	$ 8,970	$ 159,279	$ 113,471	$ 19,150	$ 19,150