Fair Value Measurements - Level 3 Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	$ 1,138	$ 1,579	$ 2,777
Original fair value of contingent consideration	1,292
Income included in general and administrative expense	6	(265)	(687)
Net purchases, issuances, sales and settlements	(1,138)	(176)	(511)
Ending balance	1,298	1,138	1,579
Contingent Consideration \| Jet Prep Ltd.
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	0	0	751
Original fair value of contingent consideration	0
Income included in general and administrative expense	0	0	(751)
Net purchases, issuances, sales and settlements	0	0	0
Ending balance	0	0	0
Contingent Consideration \| Aexis Medical
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	0	0	0
Original fair value of contingent consideration	1,292
Income included in general and administrative expense	6	0	0
Net purchases, issuances, sales and settlements	0	0	0
Ending balance	1,298	0	0
Jet Prep Assumed Contingent Obligation \| Jet Prep Ltd.
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	1,138	1,138	1,138
Original fair value of contingent consideration	0
Income included in general and administrative expense	0	0	0
Net purchases, issuances, sales and settlements	(1,138)	0	0
Ending balance	0	1,138	1,138
Cantel Medical (U.K.) Contingent Guaranteed Obligation \| Cantel Medical (UK) - PuriCore International Limited
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	0	441	888
Original fair value of contingent consideration	0
Income included in general and administrative expense	0	(265)	64
Net purchases, issuances, sales and settlements	0	(176)	(511)
Ending balance	$ 0	$ 0	$ 441

Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Liability, Contingent Consideration

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- Definition

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

+ References

No definition available.

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- Definition

Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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