Financial Information for Business Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Sep. 30, 2011
Revenues
Product	$ 117,621	$ 174,936	$ 214,719	$ 336,125
Services	21,716	17,715	44,846	34,893
Total revenues	139,337	192,651	259,565	371,018
Gross profit	48,282	61,674	88,639	118,993
Operating income (loss)	8,415	26,741	9,878	50,470
Assets	636,676		636,676		636,620
Brooks Product Solutions
Revenues
Product	103,456	121,664	188,750	233,665
Total revenues	103,456	121,664	188,750	233,665
Gross profit	35,885	47,490	64,286	90,580
Operating income (loss)	7,597	20,677	8,682	38,148
Assets	225,588		225,588		235,322
Brooks Global Services
Revenues
Product	3,015	4,149	5,392	7,447
Services	18,220	17,715	37,937	34,893
Total revenues	21,235	21,864	43,329	42,340
Gross profit	6,591	7,920	13,727	15,187
Operating income (loss)	2,195	3,062	5,144	5,572
Assets	57,192		57,192		52,354
Brooks Life Science Systems
Revenues
Product	11,150		20,577
Services	3,496		6,909
Total revenues	14,646		27,486
Gross profit	5,806		10,626
Operating income (loss)	(105)		(738)
Assets	109,314		109,314		101,331
Contract Manufacturing
Revenues
Product		49,123		95,013
Total revenues		49,123		95,013
Gross profit		6,264		13,226
Operating income (loss)		4,000		8,643
Operating Segments, Total
Revenues
Product	117,621	174,936	214,719	336,125
Services	21,716	17,715	44,846	34,893
Total revenues	139,337	192,651	259,565	371,018
Gross profit	48,282	61,674	88,639	118,993
Operating income (loss)	9,687	27,739	13,088	52,363
Assets	$ 392,094		$ 392,094		$ 389,007