Fair Value Measurements - Level 3 Liabilities (Details) - USD ($)	3 Months Ended
	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	$ 1,918,000	$ 2,050,000	$ 2,777,000	$ 2,774,000	$ 5,701,000	$ 5,807,000	$ 5,869,000
Total net unrealized (gains) losses included in general and administrative expense in earnings	20,000	21,000	(592,000)	52,000	(2,790,000)	127,000	147,000
Settlements	(95,000)	(100,000)	(120,000)	(109,000)	(161,000)	(164,000)	(132,000)
Foreign currency translation	12,000	(53,000)	(15,000)	60,000	24,000	(69,000)	(77,000)
Ending balance	1,855,000	1,918,000	2,050,000	2,777,000	2,774,000	5,701,000	5,807,000
Contingent Consideration | Jet Prep Ltd.
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	143,000	139,000	751,000	729,000	2,888,000	2,804,000	2,722,000
Total net unrealized (gains) losses included in general and administrative expense in earnings	5,000	4,000	(612,000)	22,000	(2,159,000)	84,000	82,000
Ending balance	148,000	143,000	139,000	751,000	729,000	2,888,000	2,804,000
Assumed contingent liability | Jet Prep Ltd.
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	1,138,000	1,138,000	1,138,000	1,131,000	1,773,000	1,763,000	1,752,000
Total net unrealized (gains) losses included in general and administrative expense in earnings				7,000	(642,000)	10,000	11,000
Ending balance	1,138,000	1,138,000	1,138,000	1,138,000	1,131,000	1,773,000	1,763,000
Contingent guaranteed obligation | Cantel Medical (UK)
Reconciliation of liability measured and recorded at fair value on a recurring basis using Level 3
Beginning balance	637,000	773,000	888,000	914,000	1,040,000	1,240,000	1,395,000
Total net unrealized (gains) losses included in general and administrative expense in earnings	15,000	17,000	20,000	23,000	11,000	33,000	54,000
Settlements	(95,000)	(100,000)	(120,000)	(109,000)	(161,000)	(164,000)	(132,000)
Foreign currency translation	12,000	(53,000)	(15,000)	60,000	24,000	(69,000)	(77,000)
Ending balance	$ 569,000	$ 637,000	$ 773,000	$ 888,000	$ 914,000	$ 1,040,000	$ 1,240,000