Derivatives	12 Months Ended
Jul. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives We recognize all derivatives on the balance sheet at fair value. Derivatives that are not designated as hedges must be adjusted to fair value through earnings. If the derivative is designated as a hedge, depending on the nature of the hedge, changes in the fair value of the derivative will either be offset against the change in the fair value of the hedged assets, liabilities or firm commitments through earnings or recognized in other comprehensive income until the hedged item is recognized in earnings. The ineffective portion of the change in fair value of a derivative that is designated as a hedge will be recognized immediately in earnings. As of July 31, 2018, all of our derivatives were designated as hedges. We do not hold any derivative financial instruments for speculative or trading purposes. Changes in the value of the Euro, British Pound, Singapore dollar, Canadian dollar, Australian dollar and the Chinese Renminbi against the U.S. dollar affect our results of operations because certain cash bank accounts, accounts receivable, and liabilities of Cantel and its subsidiaries are denominated and ultimately settled in U.S. dollars or these foreign currencies, but must be converted into each entity’s functional currency. In order to hedge against the impact of fluctuations in the value of the Euro, British Pound, Canadian dollar, Australian dollar and Singapore dollar relative to the U.S. dollar on the conversion of such net assets into the functional currencies, we enter into short-term forward contracts to purchase Euros, British Pounds, Canadian dollars, Australian dollars and Singapore dollars, which contracts are one-month in duration. These short-term contracts are designated as fair value hedge instruments. There were seven foreign currency forward contracts with an aggregate notional value of $30,159 at July 31, 2018, which covered certain assets and liabilities that were denominated in currencies other than each entity’s functional currency. These foreign currency forward contracts are continually replaced with new one-month contracts as long as we have significant net assets that are denominated and ultimately settled in currencies other than each entity’s functional currency. For the fiscal year ended July 31, 2018, such forward contracts partially offset the impact on operations relating to certain assets and liabilities that were denominated in currencies other than each entity’s functional currency. This resulted in an immaterial amount of net currency conversion gains, net of tax, on the hedged items. Gains and losses related to hedging contracts to buy Euros, British Pounds, Canadian dollars, Australian dollars and Singapore dollars forward are immediately realized within general and administrative expenses due to the short-term nature of such contracts. We do not currently hedge against the impact of fluctuations in the value of the Chinese Renminbi or Sri Lankan Rupee relative to the U.S. dollar because the overall foreign currency exposures relating to those currencies are currently not deemed significant.

Derivatives

We recognize all derivatives on the balance sheet at fair value. Derivatives that are not designated as hedges must be adjusted to fair value through earnings. If the derivative is designated as a hedge, depending on the nature of the hedge, changes in the fair value of the derivative will either be offset against the change in the fair value of the hedged assets, liabilities or firm commitments through earnings or recognized in other comprehensive income until the hedged item is recognized in earnings. The ineffective portion of the change in fair value of a derivative that is designated as a hedge will be recognized immediately in earnings. As of July 31, 2018, all of our derivatives were designated as hedges. We do not hold any derivative financial instruments for speculative or trading purposes.

Changes in the value of the Euro, British Pound, Singapore dollar, Canadian dollar, Australian dollar and the Chinese Renminbi against the U.S. dollar affect our results of operations because certain cash bank accounts, accounts receivable, and liabilities of Cantel and its subsidiaries are denominated and ultimately settled in U.S. dollars or these foreign currencies, but must be converted into each entity’s functional currency.

In order to hedge against the impact of fluctuations in the value of the Euro, British Pound, Canadian dollar, Australian dollar and Singapore dollar relative to the U.S. dollar on the conversion of such net assets into the functional currencies, we enter into short-term forward contracts to purchase Euros, British Pounds, Canadian dollars, Australian dollars and Singapore dollars, which contracts are one-month in duration. These short-term contracts are designated as fair value hedge instruments. There were seven foreign currency forward contracts with an aggregate notional value of $30,159 at July 31, 2018, which covered certain assets and liabilities that were denominated in currencies other than each entity’s functional currency. These foreign currency forward contracts are continually replaced with new one-month contracts as long as we have significant net assets that are denominated and ultimately settled in currencies other than each entity’s functional currency. For the fiscal year ended July 31, 2018, such forward contracts partially offset the impact on operations relating to certain assets and liabilities that were denominated in currencies other than each entity’s functional currency. This resulted in an immaterial amount of net currency conversion gains, net of tax, on the hedged items. Gains and losses related to hedging contracts to buy Euros, British Pounds, Canadian dollars, Australian dollars and Singapore dollars forward are immediately realized within general and administrative expenses due to the short-term nature of such contracts. We do not currently hedge against the impact of fluctuations in the value of the Chinese Renminbi or Sri Lankan Rupee relative to the U.S. dollar because the overall foreign currency exposures relating to those currencies are currently not deemed significant.