Schedule II Valuation of Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at beginning of period	$ 4,629	$ 5,144	$ 3,585
Additions — Charged to expense	752	732	1,904
Deductions - written off	(910)	(1,247)	(345)
Balances at end of period	4,471	4,629	5,144
Inventory Valuation Reserve [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at beginning of period	14,322	15,083	13,269
Additions — Charged to expense	2,797	4,608	4,950
Deductions - written off	(4,537)	(5,369)	(3,136)
Balances at end of period	12,582	14,322	15,083
Valuation Allowance of Deferred Tax Assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at beginning of period	38,563	37,992	39,922
Additions — Charged to expense	24,184	2,004	2,614
Deductions - written off	(5,881)	(1,433)	(4,544)
Balances at end of period	$ 56,866	$ 38,563	$ 37,992

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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- Definition

Amount of increase in the allowances and reserves, which consist of the valuation and qualifying accounts that are either netted against the cost of an asset or that reflect a liability established to represent expected future costs, from charges to costs and expenses.

+ References

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- Definition

Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

+ References

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