Acquisitions - Narrative (Details) - USD ($) $ in Thousands					12 Months Ended
	Sep. 23, 2019	Apr. 18, 2019	Jan. 29, 2019	Jul. 31, 2018	Jul. 03, 2020	Jun. 30, 2019	Jun. 30, 2018
Business Acquisition [Line Items]
Goodwill					$ 614,076	$ 562,146
Acquisition of businesses, net of cash acquired			$ 36,500		$ 96,502	$ 127,083	$ 185,396
Customer Relationships
Business Acquisition [Line Items]
Acquired intangible assets, estimated useful lives					11 years 4 months 24 days	11 years 4 months 24 days
American Panel Corporation
Business Acquisition [Line Items]
Total purchase price	$ 100,000
Identifiable intangible assets	$ 33,200
Acquired intangible assets, estimated useful lives	15 years
Goodwill	$ 52,676
Revenue from acquiree since acquisition date					$ 27,383
Earnings (loss) of acquiree since acquisition date					$ 3,309
Goodwill acquired, tax deductible amount	51,553
Acquisition of businesses, net of cash acquired	96,502
Working capital and net debt adjustment	5,952
American Panel Corporation | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets	$ 20,600
Acquired intangible assets, estimated useful lives	11 years				11 years
American Panel Corporation | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets	$ 10,400
Acquired intangible assets, estimated useful lives	11 years				11 years
American Panel Corporation | Order or Production Backlog
Business Acquisition [Line Items]
Identifiable intangible assets	$ 2,200
Acquired intangible assets, estimated useful lives	2 years				2 years
The Athena Group, Inc
Business Acquisition [Line Items]
Total purchase price		$ 34,000
Identifiable intangible assets		23,700
Goodwill		15,007
Acquisition of businesses, net of cash acquired		33,554
Working capital and net debt adjustment		446
The Athena Group, Inc | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets		$ 23,700
Acquired intangible assets, estimated useful lives		11 years
Syntonic Microwave LLC
Business Acquisition [Line Items]
Identifiable intangible assets		$ 7,100
Acquired intangible assets, estimated useful lives		15 years
Goodwill		$ 4,232
Goodwill acquired, tax deductible amount					$ 2,986
Acquisition of businesses, net of cash acquired		12,000
Syntonic Microwave LLC | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets		$ 4,200
Acquired intangible assets, estimated useful lives		10 years
Syntonic Microwave LLC | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets		$ 2,500
Acquired intangible assets, estimated useful lives		9 years
Syntonic Microwave LLC | Order or Production Backlog
Business Acquisition [Line Items]
Identifiable intangible assets		$ 400
Acquired intangible assets, estimated useful lives		1 year
GECO Avionics, LLC
Business Acquisition [Line Items]
Total purchase price			36,500
Identifiable intangible assets			$ 12,700
Acquired intangible assets, estimated useful lives			15 years
Goodwill			$ 21,023
Goodwill acquired, tax deductible amount					19,766
Acquisition of businesses, net of cash acquired			36,500
GECO Avionics, LLC | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets			$ 6,900,000
Acquired intangible assets, estimated useful lives			11 years
GECO Avionics, LLC | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets			$ 4,800,000
Acquired intangible assets, estimated useful lives			10 years
GECO Avionics, LLC | Order or Production Backlog
Business Acquisition [Line Items]
Identifiable intangible assets			$ 1,000,000
Acquired intangible assets, estimated useful lives			2 years
Germane Systems, LC
Business Acquisition [Line Items]
Total purchase price				$ 45,000
Identifiable intangible assets				$ 12,910
Acquired intangible assets, estimated useful lives				15 years
Goodwill				$ 23,558
Goodwill acquired, tax deductible amount					$ 20,555
Acquisition of businesses, net of cash acquired				45,729
Working capital and net debt adjustment				1,244
Germane Systems, LC | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets				$ 8,500
Acquired intangible assets, estimated useful lives				11 years
Germane Systems, LC | Developed Technology
Business Acquisition [Line Items]
Identifiable intangible assets				$ 4,200
Acquired intangible assets, estimated useful lives				8 years
Germane Systems, LC | Order or Production Backlog
Business Acquisition [Line Items]
Identifiable intangible assets				$ 210
Acquired intangible assets, estimated useful lives				1 year