Schedule II Valuation of Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at beginning of period	$ 5,005	$ 4,471	$ 4,629
Additions — Charged to expense	2,495	587	752
Deductions - written off	(343)	(53)	(910)
Balances at end of period	7,157	5,005	4,471
SEC Schedule, 12-09, Reserve, Inventory [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at beginning of period	13,404	12,582	14,322
Additions — Charged to expense	5,722	3,168	2,797
Deductions - written off	(2,817)	(2,346)	(4,537)
Balances at end of period	16,309	13,404	12,582
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at beginning of period	60,073	56,866	38,563
Additions — Charged to expense	6,204	5,981	24,184
Deductions - written off	(7,468)	(2,774)	(5,881)
Balances at end of period	$ 58,809	$ 60,073	$ 56,866