Acquisitions - Narrative (Details) - USD ($)							12 Months Ended
	Apr. 19, 2019	Apr. 18, 2019	Jan. 29, 2019	Jul. 31, 2018	Jul. 13, 2018	Feb. 01, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Business Acquisition [Line Items]
Goodwill							$ 562,146,000	$ 497,442,000
Acquisition of businesses, net of cash acquired			$ 36,500,000				$ 127,083,000	$ 185,396,000	$ 77,757,000
Customer Relationships
Business Acquisition [Line Items]
Acquired intangible assets, estimated useful lives							11 years 4 months 24 days	10 years 8 months 12 days
The Athena Group, Inc
Business Acquisition [Line Items]
Total purchase price		$ 34,000,000
Fair value of identifiable intangible assets		23,700,000
Goodwill		15,999,000
Revenue from acquiree since acquisition date							$ 1,071
Earnings (loss) of acquiree since acquisition date							93
Acquisition of businesses, net of cash acquired	$ 33,554,000	33,554,000
Working capital and net debt adjustment		446,000
The Athena Group, Inc | Developed Technology
Business Acquisition [Line Items]
Fair value of identifiable intangible assets		$ 23,700,000,000
Acquired intangible assets, estimated useful lives		11 years
Syntonic Microwave LLC
Business Acquisition [Line Items]
Fair value of identifiable intangible assets		$ 7,100,000
Acquired intangible assets, estimated useful lives		15 years
Goodwill		$ 4,232,000
Revenue from acquiree since acquisition date							993
Earnings (loss) of acquiree since acquisition date							133
Goodwill acquired, tax deductible amount							3,092
Acquisition of businesses, net of cash acquired		12,000,000
Syntonic Microwave LLC | Customer Relationships
Business Acquisition [Line Items]
Fair value of identifiable intangible assets		$ 4,200,000,000
Acquired intangible assets, estimated useful lives		10 years
Syntonic Microwave LLC | Developed Technology
Business Acquisition [Line Items]
Fair value of identifiable intangible assets		$ 2,500,000,000
Acquired intangible assets, estimated useful lives		9 years
Syntonic Microwave LLC | Order or Production Backlog
Business Acquisition [Line Items]
Fair value of identifiable intangible assets		$ 400,000,000
Acquired intangible assets, estimated useful lives		1 year
GECO Avionics, LLC
Business Acquisition [Line Items]
Total purchase price			36,500,000
Fair value of identifiable intangible assets			$ 12,500,000
Acquired intangible assets, estimated useful lives			15 years
Goodwill			$ 21,223,000
Revenue from acquiree since acquisition date							6,834
Earnings (loss) of acquiree since acquisition date							(112)
Goodwill acquired, tax deductible amount							20,984,000
Acquisition of businesses, net of cash acquired			36,500,000
GECO Avionics, LLC | Customer Relationships
Business Acquisition [Line Items]
Fair value of identifiable intangible assets			$ 6,700,000,000
Acquired intangible assets, estimated useful lives			11 years
GECO Avionics, LLC | Developed Technology
Business Acquisition [Line Items]
Fair value of identifiable intangible assets			$ 4,800,000,000
Acquired intangible assets, estimated useful lives			10 years
GECO Avionics, LLC | Order or Production Backlog
Business Acquisition [Line Items]
Fair value of identifiable intangible assets			$ 1,000,000,000
Acquired intangible assets, estimated useful lives			2 years
Germane Systems, LC
Business Acquisition [Line Items]
Total purchase price				$ 45,000,000,000
Fair value of identifiable intangible assets				$ 12,910,000
Acquired intangible assets, estimated useful lives				15 years
Goodwill				$ 23,111,000
Revenue from acquiree since acquisition date							46,767
Earnings (loss) of acquiree since acquisition date							3,132
Goodwill acquired, tax deductible amount							$ 22,102,000
Acquisition of businesses, net of cash acquired				45,729,000
Working capital and net debt adjustment				1,244,000
Germane Systems, LC | Customer Relationships
Business Acquisition [Line Items]
Fair value of identifiable intangible assets				$ 8,500,000,000
Acquired intangible assets, estimated useful lives				11 years
Germane Systems, LC | Developed Technology
Business Acquisition [Line Items]
Fair value of identifiable intangible assets				$ 4,200,000,000
Acquired intangible assets, estimated useful lives				8 years
Germane Systems, LC | Order or Production Backlog
Business Acquisition [Line Items]
Fair value of identifiable intangible assets				$ 210,000,000
Acquired intangible assets, estimated useful lives				1 year
Themis Computer Acquisition
Business Acquisition [Line Items]
Total purchase price						$ 180,000,000
Fair value of identifiable intangible assets						71,720,000
Goodwill						112,987,000
Acquisition of businesses, net of cash acquired						179,005,000
Working capital and net debt adjustment						1,274,000
Post closing adjustments					$ 700,000
Themis Computer Acquisition | Customer Relationships
Business Acquisition [Line Items]
Fair value of identifiable intangible assets						$ 52,600,000
Acquired intangible assets, estimated useful lives						12 years 6 months
Themis Computer Acquisition | Developed Technology
Business Acquisition [Line Items]
Fair value of identifiable intangible assets						$ 17,150,000
Acquired intangible assets, estimated useful lives						9 years 6 months
Themis Computer Acquisition | Order or Production Backlog
Business Acquisition [Line Items]
Fair value of identifiable intangible assets						$ 1,970,000
Acquired intangible assets, estimated useful lives						1 year