Revenue (Details) - USD ($)	3 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Jul. 31, 2021
Revenue from Contract with Customer [Abstract]
Allowance for doubtful accounts	$ 0		$ 0
Contract costs, current	13,805,000		13,365,000
Contract costs, noncurrent	29,061,000		$ 28,870,000
Amortization of contract costs	3,001,000	$ 2,154,000
Contract with customer, liability, revenue recognized	67,000,000
Remaining performance obligation, amount	$ 881,000,000