Goodwill Goodwill - Changes in Carrying Amount of Goodwill (Detail) $ in Thousands	12 Months Ended
Jun. 30, 2019 USD ($)
Goodwill [Roll Forward]
Beginning Balance	$ 497,442
Ending Balance	562,146
Sensor And Mission Processing [Member]
Goodwill [Roll Forward]
Beginning Balance	119,560
Ending Balance	140,783
AMS [Member]
Goodwill [Roll Forward]
Beginning Balance	218,147
Ending Balance	222,379
MDS
Goodwill [Roll Forward]
Beginning Balance	159,735
Ending Balance	198,984
RTL
Goodwill [Roll Forward]
Goodwill arising from acquisition	4,232
RTL \| AMS [Member]
Goodwill [Roll Forward]
Goodwill arising from acquisition	4,232
Themis
Goodwill [Roll Forward]
Goodwill adjustments	139
Themis \| MDS
Goodwill [Roll Forward]
Goodwill adjustments	139
The Athena Group, Inc [Member]
Goodwill [Roll Forward]
Goodwill arising from acquisition	15,999
The Athena Group, Inc [Member] \| MDS
Goodwill [Roll Forward]
Goodwill arising from acquisition	$ 15,999

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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