Acquisitions - Goodwill (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Apr. 20, 2018	Apr. 06, 2018	Oct. 05, 2017	Sep. 30, 2017	Jul. 05, 2017	Nov. 28, 2016	Sep. 30, 2016	Nov. 30, 2015
Goodwill
Goodwill	$ 255,876				$ 207,154			$ 175,654
Brooks Semiconductor Solutions Group
Goodwill
Goodwill	47,963				40,334			40,353
Brooks Life Sciences
Goodwill
Goodwill	$ 207,913				$ 166,820			$ 135,301
Tec-Sem Group AG
Goodwill
Goodwill			$ 7,665
Goodwill deductible for tax purposes			0
Tec-Sem Group AG | Brooks Semiconductor Solutions Group
Goodwill
Goodwill			$ 7,700
4titude Limited
Goodwill
Goodwill				$ 38,185
Goodwill deductible for tax purposes				$ 0
BioSpeciMan Corporation
Goodwill
Goodwill		$ 2,700
Goodwill deductible for tax purposes		0
BioSpeciMan Corporation | Brooks Life Sciences
Goodwill
Goodwill		$ 2,700
PBMMI and Novare
Goodwill
Goodwill						$ 21,434
Goodwill deductible for tax purposes						$ 21,434
Cool Lab, LLC
Goodwill
Goodwill							$ 8,527
Goodwill deductible for tax purposes							$ 8,527
BioStorage Technologies, Inc.
Goodwill
Goodwill									$ 79,639
Goodwill deductible for tax purposes									$ 0