Restructuring and Other Charges - General Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 1,894	$ 714	$ 3,144
Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges			1,894	$ 714	3,144
Corporate, Non-Segment | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges					300
Brooks Semiconductor Solutions Group
Restructuring Cost and Reserve [Line Items]
Restructuring charges			600
Brooks Semiconductor Solutions Group | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 300			2,500
Brooks Life Sciences
Restructuring Cost and Reserve [Line Items]
Restructuring charges			1,900
Additional Restructuring Charges			$ 700
Severance Costs	$ 600
Brooks Life Sciences | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 300			400
Actions Initiated During Fiscal Year 2017 | Brooks Semiconductor Solutions Group | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges					1,500
Actions Initiated During Fiscal Year 2016 | Brooks Semiconductor Solutions Group | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges					$ 1,000