Accounts Receivable (Details) - USD ($)	3 Months Ended	12 Months Ended
	Oct. 31, 2024	Jul. 31, 2024
Statement [Line Items]
Total accounts receivable	$ 200,239,000	$ 197,527,000
Less allowance for doubtful accounts	19,375,000	1,932,000
Accounts receivable, net	180,864,000	$ 195,595,000
Unbilled receivables, not billable	18,993,000
Cumulative earnings (deficit)	(1,551,000)
Accounts Receivable
Statement [Line Items]
Unbilled receivables, not billable	17,442,000
Modular Transportable Transmission Systems
Statement [Line Items]
Cumulative earnings (deficit)	1,004,000
CGC Divestiture
Statement [Line Items]
Unbilled receivables, not billable	3,003,000
Cumulative earnings (deficit)	4,157,000
Nonrecurring Engineering Projects
Statement [Line Items]
Unbilled receivables, not billable	1,281,000
Cumulative earnings (deficit)	$ 1,360,000
Accounts Receivable | Customer Concentration Risk | U.S. government
Statement [Line Items]
Concentration risk, percentage	34.70%	36.40%
Accounts Receivable | Customer Concentration Risk | AT&T, Inc.
Statement [Line Items]
Concentration risk, percentage	11.40%	10.90%
Accounts Receivable | Customer Concentration Risk | U.K.
Statement [Line Items]
Concentration risk, percentage	11.60%	11.30%
Billed Receivables | Commercial and International Customers
Statement [Line Items]
Total accounts receivable	$ 56,824,000	$ 53,108,000
Billed Receivables | U.S. Government and Its Agencies
Statement [Line Items]
Total accounts receivable	31,747,000	20,682,000
Unbilled Receivables
Statement [Line Items]
Long-term receivables		824,000
Unbilled Receivables | Commercial and International Customers
Statement [Line Items]
Total accounts receivable	73,896,000	72,540,000
Unbilled Receivables | U.S. Government and Its Agencies
Statement [Line Items]
Total accounts receivable	$ 37,772,000	$ 51,197,000