Goodwill and Intangible Assets - Reporting Segments (Details) - segment	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Goodwill [Line Items]
Number of Reporting Units	5	5	5	5
Brooks Semiconductor Solutions Group
Goodwill [Line Items]
Number of Reporting Units	3	3	3	3
Brooks Life Sciences
Goodwill [Line Items]
Number of Reporting Units	2	2	2	2