Goodwill (Details)	3 Months Ended
Oct. 31, 2020 USD ($) operating_segment	Aug. 01, 2020 $ / shares
Goodwill [Roll Forward]
Balance as of July 31, 2020	$ 330,519,000
Balance as of October 31, 2020	$ 331,487,000
Number of operating segments \| operating_segment	2
Common Stock
Goodwill [Roll Forward]
Share price (in dollars per share) \| $ / shares		$ 16.42
CGC
Goodwill [Roll Forward]
Balance as of July 31, 2020	$ 15,894,000
Change related to CGC acquisition	(84,000)
Balance as of October 31, 2020	15,810,000
Solacom
Goodwill [Roll Forward]
Change related to Solacom Technologies Inc. ("Solacom")	1,052,000
Commercial Solutions
Goodwill [Roll Forward]
Balance as of July 31, 2020	255,432,000
Balance as of October 31, 2020	256,484,000
Percentage of fair value in excess of carrying amount for reporting unit		8.40%
Commercial Solutions \| CGC
Goodwill [Roll Forward]
Change related to CGC acquisition	0
Commercial Solutions \| Solacom
Goodwill [Roll Forward]
Change related to Solacom Technologies Inc. ("Solacom")	1,052,000
Government Solutions
Goodwill [Roll Forward]
Balance as of July 31, 2020	75,087,000
Balance as of October 31, 2020	75,003,000
Percentage of fair value in excess of carrying amount for reporting unit		78.00%
Government Solutions \| CGC
Goodwill [Roll Forward]
Change related to CGC acquisition	(84,000)
Government Solutions \| Solacom
Goodwill [Roll Forward]
Change related to Solacom Technologies Inc. ("Solacom")	$ 0

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.

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