Revenue from Contracts with Customers - Disaggregated By Reporting Unit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 315,349	$ 220,350	$ 851,439	$ 651,077
Automation Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 122,567	$ 81,656	$ 320,540	$ 214,627
Reporting unit, name of segment	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group
Contamination Control Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 50,742	$ 34,780	$ 117,236	$ 124,584
Reporting unit, name of segment	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group
Global Semiconductor Services
Disaggregation of Revenue [Line Items]
Total revenue	$ 12,953	$ 10,616	$ 36,898	$ 31,575
Reporting unit, name of segment	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group	Brooks Semiconductor Solutions Group
Brooks Life Sciences Products
Disaggregation of Revenue [Line Items]
Total revenue	$ 48,625	$ 30,421	$ 146,490	$ 91,138
Reporting unit, name of segment	Brooks Life Sciences Products	Brooks Life Sciences Products	Brooks Life Sciences Products	Brooks Life Sciences Products
Brooks Life Sciences Services
Disaggregation of Revenue [Line Items]
Total revenue	$ 80,462	$ 62,877	$ 230,275	$ 189,153
Reporting unit, name of segment	Brooks Life Sciences Services	Brooks Life Sciences Services	Brooks Life Sciences Services	Brooks Life Sciences Services
Brooks Semiconductor Solutions Group
Disaggregation of Revenue [Line Items]
Total revenue	$ 186,262	$ 127,052	$ 474,674	$ 370,786