Acquisitions (Narrative) (Details)						3 Months Ended		6 Months Ended				12 Months Ended
	Jan. 31, 2020 USD ($)	Jan. 27, 2020 USD ($) $ / shares shares	Aug. 01, 2019 USD ($)	Apr. 29, 2019 USD ($) employee	Feb. 28, 2019 USD ($) $ / shares shares	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Sep. 30, 2020 USD ($) $ / shares	Jul. 31, 2020 USD ($)	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)	Jul. 31, 2018 USD ($)
Business Acquisition [Line Items]
Payable subject to closing conditions										$ 750,000	$ 0
Revenue						$ 161,654,000	$ 164,133,000			331,921,000	324,977,000
Operating income						6,234,000	12,413,000			15,494,000	19,706,000
Cash and cash equivalents	$ 46,471,000					46,471,000	$ 45,997,000			46,471,000	$ 45,997,000		$ 45,576,000	$ 43,484,000
Debt	158,000,000					158,000,000				158,000,000			$ 165,000,000
Solacom
Business Acquisition [Line Items]
Aggregate purchase price					$ 32,934,000
Aggregate purchase price - settled in cash					27,328,000
Aggregate purchase price - settled with issuance of common stock					$ 5,606,000
Aggregate purchase price - settled with issuance of common stock (in shares) | shares					208,669
Weighted average stock price (in dollars per share) | $ / shares					$ 26.86
Consideration transferred, net of cash acquired					$ 31,489,000
Cash acquired from acquisition					$ 1,445,000
GD NG-911 business
Business Acquisition [Line Items]
Aggregate purchase price	10,000,000			$ 10,000,000
Development contract term				5 years
Number of employees hired | employee				60
Amortization period of other liabilities				5 years 3 months
Goodwill amount estimated to be tax deductible				$ 10,505,000
Proposed upward adjustment			$ 2,900,000
Proposed reduction to the purchase price			$ 1,000,000
CGC Technology
Business Acquisition [Line Items]
Aggregate purchase price		$ 23,650,000
Aggregate purchase price - settled in cash		12,075,000
Aggregate purchase price - settled with issuance of common stock		$ 11,575,000
Aggregate purchase price - settled with issuance of common stock (in shares) | shares		323,504
Weighted average stock price (in dollars per share) | $ / shares		$ 35.78
Consideration transferred, net of cash acquired		$ 22,740,000
Cash acquired from acquisition		160,000
Payable subject to closing conditions		$ 750,000
Forecast | UHP Networks
Business Acquisition [Line Items]
Aggregate purchase price									$ 40,000,000
Aggregate purchase price - settled with issuance of common stock									5,000,000
Earn out additional payable									$ 10,000,000
Earn out additional payable, term									12 months
Forecast | Gilat
Business Acquisition [Line Items]
Aggregate purchase price								$ 560,083,000
Consideration, cash, per share (in usd per share) | $ / shares								$ 7.18
Consideration, shares, share issuance ratio								0.08425
Transaction related costs, capitalized and expensed								$ 28,640,000
Gilat
Business Acquisition [Line Items]
Revenue												$ 263,492,000
Operating income												25,572,000
Cash and cash equivalents												74,778,000
Debt												$ 8,096,000
Secured Credit Facility
Business Acquisition [Line Items]
Secured credit facility, maximum borrowing capacity	$ 550,000,000					$ 550,000,000				$ 550,000,000
Secured Credit Facility | Forecast
Business Acquisition [Line Items]
Secured credit facility, maximum borrowing capacity								$ 800,000,000