Commitments and Contingencies - Annual Required Payments (Details)
 3 Months Ended
Oct. 31, 2016
USD ($)
Minimum commitments under noncancelable operating leases  
Remaining fiscal year $ 4,753,000
2018 5,460,000
2019 4,379,000
2020 3,064,000
2021 2,181,000
Thereafter 3,454,000
Total 23,291,000
Total contractual obligations  
Remaining fiscal year 13,566,000
2018 12,008,000
2019 168,354,000
2020 3,820,000
2021 2,841,000
Thereafter 4,476,000
Total 205,065,000
Compensation agreements  
Other commitments  
Remaining fiscal year 6,040,000
2018 2,882,000
2019 691,000
2020 498,000
2021 377,000
Thereafter 583,000
Total 11,071,000
Assumed contingent liability  
Other commitments  
Remaining fiscal year 19,000
2018 93,000
2019 188,000
2020 246,000
2021 280,000
Thereafter 439,000
Total $ 1,265,000
Assumed contingent liability | Jet Prep Ltd.  
Total contractual obligations  
Discount rate of potential payments (as a percent) 2.50%
Assumed contingent obligation $ 1,138,000
Contingent guaranteed obligation  
Other commitments  
Remaining fiscal year 122,000
2018 123,000
2019 112,000
Total $ 357,000
Contingent guaranteed obligation | Cantel Medical (UK) - PuriCore International Limited  
Total contractual obligations  
Discount rate of potential payments (as a percent) 10.10%
Contingent guaranteed obligation $ 349,000
Other long-term obligations  
Other commitments  
Remaining fiscal year 205,000
2018 214,000
2019 96,000
2020 12,000
2021 3,000
Total 530,000
Credit Agreement  
Maturity of the credit facility  
2019 161,000,000
Total 161,000,000
Expected interest payments under the credit facility  
Remaining fiscal year 2,427,000
2018 3,236,000
2019 1,888,000
Total $ 7,551,000
Total contractual obligations  
Weighted average interest rate on outstanding borrowings (as a percent) 2.01%