Acquisitions - Escrow (Details) - GENEWIZ - USD ($) $ in Millions		12 Months Ended
Nov. 15, 2018	Sep. 30, 2019
Business Acquisition [Line Items]
Escrow deposit	$ 32.3
Escrow deposit for acquiree's employees retention obligations	1.5
Reversal of liability associated with adjustment holdback		$ 1.5
Seller's cash	$ 0.7
Escrow collected		$ 1.8

Escrow Deposit for Acquiree's Employees Retention Obligations

No definition available.

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

- Definition

Escrow Deposit Withdrawn

+ References

No definition available.

+ Details

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

- Definition

Reversal of Liability Associated with Adjustment Holdback

+ References

No definition available.

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow associated with the acquisition of business during the period (for example, cash that was held by the acquired business).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

+ Details

Name:	us-gaap_CashAcquiredFromAcquisition
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_EscrowDeposit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: