Fair Value Measurements - Recurring Basis (Details) - USD ($) $ in Thousands	Jul. 31, 2017	Jul. 31, 2016
Jet Prep Ltd.
Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis
Assumed contingent obligation	$ 1,138
Level 3 | Recurring basis | Cantel Medical (UK) - PuriCore International Limited
Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis
Fair value of contingent liability	0	$ 441
Level 3 | Recurring basis | Jet Prep Ltd.
Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis
Assumed contingent obligation	$ 1,138