Goodwill and Intangible Assets - Components of Goodwill by Business Segment (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Goodwill [Roll Forward]
Gross goodwill, period start	$ 712,882	$ 679,292
Acquisitions and adjustments during fiscal year	11,577	33,590
Gross goodwill, period end	724,459	712,882
Accumulated goodwill impairments, beginning balance	(614,958)	(614,958)
Impairments recorded during fiscal year	0	0
Accumulated goodwill impairments, ending balance	(614,958)	(614,958)
Goodwill, less accumulated impairments	109,501	97,924
Brooks Product Solutions
Goodwill [Roll Forward]
Gross goodwill, period start	482,637	461,738
Acquisitions and adjustments during fiscal year	11,638	20,899
Gross goodwill, period end	494,275	482,637
Accumulated goodwill impairments, beginning balance	(437,706)	(437,706)
Impairments recorded during fiscal year	0	0
Accumulated goodwill impairments, ending balance	(437,706)	(437,706)
Goodwill, less accumulated impairments	56,569	44,931
Brooks Global Services
Goodwill [Roll Forward]
Gross goodwill, period start	156,792	151,238
Acquisitions and adjustments during fiscal year	0	5,554
Gross goodwill, period end	156,792	156,792
Accumulated goodwill impairments, beginning balance	(151,238)	(151,238)
Impairments recorded during fiscal year	0	0
Accumulated goodwill impairments, ending balance	(151,238)	(151,238)
Goodwill, less accumulated impairments	5,554	5,554
Brooks Life Science Systems
Goodwill [Roll Forward]
Gross goodwill, period start	47,439	40,302
Acquisitions and adjustments during fiscal year	(61)	7,137
Gross goodwill, period end	47,378	47,439
Accumulated goodwill impairments, beginning balance	0	0
Impairments recorded during fiscal year	0	0
Accumulated goodwill impairments, ending balance	0	0
Goodwill, less accumulated impairments	47,378	47,439
Other
Goodwill [Roll Forward]
Gross goodwill, period start	26,014	26,014
Acquisitions and adjustments during fiscal year	0	0
Gross goodwill, period end	26,014	26,014
Accumulated goodwill impairments, beginning balance	(26,014)	(26,014)
Impairments recorded during fiscal year	0	0
Accumulated goodwill impairments, ending balance	(26,014)	(26,014)
Goodwill, less accumulated impairments	$ 0	$ 0