Restructuring and Other Charges Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2016	Sep. 30, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 975	$ 1,475
Restructuring reserve	3,227	1,654	$ 5,939	$ 2,073
Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,610
Restructuring reserve		1,654		1,640
Facilities and other contract termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges		(135)
Restructuring reserve		0		$ 433
Brooks Semiconductor Solutions Group
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,100
Restructuring reserve	200
Brooks Semiconductor Solutions Group | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges		700
Brooks Life Science Systems | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,200	900
Restructuring reserve	100
Actions Initiated in Prior Periods | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	700
Actions Initiated in Prior Periods | Brooks Semiconductor Solutions Group
Restructuring Cost and Reserve [Line Items]
Restructuring charges	200	700
Actions Initiated in Prior Periods | Brooks Semiconductor Solutions Group | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,800
Restructuring reserve	1,700
Company-wide Action | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	6,500	1,640
Restructuring reserve	1,300
Costs Incurred in Prior Periods | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	5,800
Costs Incurred in Prior Periods | Brooks Semiconductor Solutions Group
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,000
Costs Incurred in Prior Periods | Brooks Life Science Systems | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,100
Actions Initiated in Current Period | Brooks Semiconductor Solutions Group | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0
Actions Initiated in Current Period | Brooks Life Science Systems
Restructuring Cost and Reserve [Line Items]
Restructuring charges	100	$ 900
Actions Initiated in Current Period | Brooks Life Science Systems | Workforce-related termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 100