Revenue from Contracts with Customers - Disaggregated By Reporting Unit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 220,350	$ 203,880	$ 651,077	$ 581,637
Automation Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 81,656	$ 77,410	$ 214,627	$ 223,531
Reporting unit, name of segment	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember
Contamination Control Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 34,780	$ 28,606	$ 124,584	$ 86,610
Reporting unit, name of segment	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember
Global Semiconductor Services
Disaggregation of Revenue [Line Items]
Total revenue	$ 10,616	$ 10,024	$ 31,575	$ 31,483
Reporting unit, name of segment	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember	brks:BrooksSemiconductorSolutionsGroupMember
Life Science Products
Disaggregation of Revenue [Line Items]
Total revenue	$ 30,421	$ 28,022	$ 91,138	$ 86,933
Reporting unit, name of segment	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember
Sample Repository Solutions
Disaggregation of Revenue [Line Items]
Total revenue	$ 25,591	$ 22,761	$ 70,878	$ 66,742
Reporting unit, name of segment	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember
GENEWIZ
Disaggregation of Revenue [Line Items]
Total revenue	$ 37,286	$ 37,057	$ 118,275	$ 86,338
Reporting unit, name of segment	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember	brks:BrooksLifeSciencesMember
Brooks Semiconductor Solutions Group
Disaggregation of Revenue [Line Items]
Total revenue	$ 127,052	$ 116,040	$ 370,786	$ 341,624
Brooks Life Sciences
Disaggregation of Revenue [Line Items]
Total revenue	$ 93,298	$ 87,840	$ 280,291	$ 240,013