CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,711us-gaap_ProfitLoss	$ 3,265us-gaap_ProfitLoss	$ (23)us-gaap_ProfitLoss	$ 6,761us-gaap_ProfitLoss
Change in cumulative translation adjustment	(2,423)	(547)	(6,565)	(841)
Change in unrealized gain on marketable securities	267	22	202	21
Change in fair value on cash flow hedges	0	(37)	0	68
Actuarial gain (loss)	(13)	10	9	21
Comprehensive income (loss)	542	2,713	(6,377)	6,030
Comprehensive income attributable to noncontrolling interests	0	(76)	0	(124)
Comprehensive income (loss) attributable to Brooks Automation, Inc.	$ 542us-gaap_ComprehensiveIncomeNetOfTax	$ 2,637us-gaap_ComprehensiveIncomeNetOfTax	$ (6,377)us-gaap_ComprehensiveIncomeNetOfTax	$ 5,906us-gaap_ComprehensiveIncomeNetOfTax

Other Comprehensive Income Change In Net Actuarial Gain Loss Tax

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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