Income Taxes - Additional Information (Details) $ in Millions	6 Months Ended
Mar. 31, 2019 USD ($)
Income Tax Disclosure [Abstract]
Toll charge, reduction in provisional accrual	$ 1.1

Income Taxes, Tax Cuts and Jobs Act, Toll Charge, Reduction in Provisional Accrual

No definition available.

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Namespace Prefix:	brks_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration