Investment in Affiliates - Additional information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of joint ventures	$ 2,133,000	$ 4,815,000	$ 1,074,000
ULVAC Cryogenics, Inc.
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of joint ventures	2,000,000	4,300,000	1,000,000
Management fee payments received	1,000,000	1,100,000	700,000
Charges for products or services	800,000	400,000	300,000
Joint venture interest, percentage	50.00%	50.00%	50.00%
Accounts payable for unpaid products and services	100,000	100,000
Cash dividend received	5,100,000	2,400,000
Yaskawa Brooks Automation, Inc.
Schedule of Equity Method Investments [Line Items]
Equity in earnings (losses) of joint ventures	100,000	500,000	100,000
Charges for products or services	500,000	300,000	200,000
Joint venture interest, percentage	50.00%	50.00%	50.00%
Accounts payable for unpaid products and services	100,000	100,000
Revenues earned from joint ventures	8,000,000	9,600,000	13,500,000
Amount due from joint ventures	$ 2,000,000	$ 2,200,000