Discontinued Operations - Non-cash Items and Capital Expenditures (Details) - Discontinued Operations, Held-for-sale - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Discontinued Operation, Alternative Cash Flow Information [Abstract]
Depreciation and amortization	$ 4	$ 743
Capital expenditures	666	302
Stock-based compensation	635	966
Earnings of equity method investment	$ (6,188)	$ (6,788)

Discontinued Operation Earnings Losses of Equity Method Investments

No definition available.

Name:	brks_DiscontinuedOperationEarningsLossesOfEquityMethodInvestments
Namespace Prefix:	brks_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Stock Based Compensation Discontinued Operations

+ References

No definition available.

+ Details

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

- Definition

Amount of capital expenditure attributable to discontinued operations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760

+ Details

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

- Definition

Amount of deprecation and amortization expense attributable to property, plant and equipment and intangible assets of discontinued operations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760

+ Details

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

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DiscontinuedOperationsHeldforsaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: