Equity Method Investments and Other Investments - Additional information (Detail) - USD ($)					1 Months Ended	12 Months Ended
	Sep. 11, 2015	Mar. 20, 2015	Feb. 02, 2015	Dec. 22, 2014	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Mar. 08, 2016
Schedule of Equity Method Investments [Line Items]
Equity in (losses) earnings of equity method investments						$ 2,380,000	$ (164,000)	$ 1,235,000
Equity method investments						27,273,000	24,308,000
Debt conversion, converted instrument, rate					9.00%
Disbursement for a loan receivable						$ 1,821,000	0	0
Percentage of income from equity method investment, in excess of income tax provision						20.00%
Goodwill						$ 202,138,000	121,408,000	109,501,000
BioCision, LLC
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage					22.00%	20.00%
Equity investment cost					$ 4,000,000
Equity in (losses) earnings of equity method investments						$ (1,100,000)	(1,000,000)
Equity method investments						1,700,000	2,700,000
Warrants aggregate fair value (less than)						100,000	100,000
Gain (Loss) on Convertible Debt Securities and Warrants Recognized in Earnings						400,000	400,000
Disbursement for a loan receivable						$ 150,000
Equity Method Investment, Quarterly Royalty Receivable, Percentage of Revenue						15.00%
ULVAC Cryogenics, Inc.
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage						50.00%
Equity in (losses) earnings of equity method investments						$ 3,400,000	1,400,000	1,600,000
Equity method investments						25,600,000	21,500,000
Charges for products or services						300,000	400,000	400,000
Accounts payable for unpaid products and services						50,298
Management fee payments received						800,000	600,000	600,000
Cash dividend received						$ 1,500,000	600,000
Yaskawa Brooks Automation, Inc.
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage						50.00%
Equity in (losses) earnings of equity method investments							(600,000)	(100,000)
Charges for products or services							700,000	700,000
Revenues earned from joint ventures							2,500,000	$ 7,400,000
Due from joint venture						$ 0
Business acquisition, cash payment		$ 1,800,000
Goodwill		$ 200,000
Dividends	$ 1,800,000
Equity Method Investment, Other than Temporary Impairment							700,000
Liquidation costs							200,000
Convertible Debt Securities [Member] | BioCision, LLC
Schedule of Equity Method Investments [Line Items]
Investment maturity period					5 years
Payments to acquire investments			$ 5,000,000	$ 2,500,000
Convertible debt securities						5,800,000	$ 5,300,000
Permanent Term Loan, Tranche One [Member] | BioCision, LLC
Schedule of Equity Method Investments [Line Items]
Receivable with Imputed Interest, Face Amount						$ 600,000			$ 750,000
Receivable with Imputed Interest, Effective Yield (Interest Rate)						10.00%
Permanent Term Loan [Member] | BioCision, LLC
Schedule of Equity Method Investments [Line Items]
Receivable with Imputed Interest, Face Amount						$ 1,500,000
Aggregate Royalty Proceeds						$ 1,500,000