Revenue from Contracts with Customers - Disaggregated By Reporting Unit (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 249,503	$ 210,500
Automation Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 90,423	$ 64,238
Reporting unit, name of segment	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember
Contamination Control Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 29,209	$ 44,340
Reporting unit, name of segment	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember
Global Semiconductor Services
Disaggregation of Revenue [Line Items]
Total revenue	$ 11,726	$ 10,233
Reporting unit, name of segment	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember
Brooks Life Sciences Products
Disaggregation of Revenue [Line Items]
Total revenue	$ 45,511	$ 29,724
Reporting unit, name of segment	brks:BrooksLifeSciencesProductsMember	brks:BrooksLifeSciencesProductsMember
Sample Repository Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 20,533	$ 21,994
Reporting unit, name of segment	brks:BrooksLifeSciencesServicesMember	brks:BrooksLifeSciencesServicesMember
GENEWIZ
Disaggregation of Revenue [Line Items]
Total revenue	$ 52,101	$ 39,971
Reporting unit, name of segment	brks:BrooksLifeSciencesServicesMember	brks:BrooksLifeSciencesServicesMember
Brooks Semiconductor Solutions Group
Disaggregation of Revenue [Line Items]
Total revenue	$ 131,358	$ 118,811
Brooks Life Sciences Products
Disaggregation of Revenue [Line Items]
Total revenue	45,511	29,724
Brooks Life Sciences Services
Disaggregation of Revenue [Line Items]
Total revenue	$ 72,634	$ 61,965