Investment in Affiliates - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of joint ventures	$ 2,782,000	$ 215,000	$ (213,000)
Sales revenues	688,105,000	592,972,000	218,706,000
ULVAC Cryogenics, Inc.
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage	50.00%	50.00%	50.00%
Equity in earnings (losses) of joint ventures	2,300,000	100,000	100,000
Management fee payments received	1,100,000	700,000	600,000
Charges for products or services	400,000	300,000	400,000
Accounts payable for unpaid products and services	100,000	0
Cash dividend	2,400,000
Yaskawa Brooks Automation, Inc.
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage	50.00%	50.00%	50.00%
Equity in earnings (losses) of joint ventures	500,000	100,000	(400,000)
Sales revenues	9,600,000	13,500,000	6,700,000
Due from joint ventures	2,200,000	4,500,000
Charges for products or services	300,000	200,000	600,000
Accounts payable for unpaid products and services	$ 100,000	$ 100,000