CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($)	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Treasury Stock	Total Brooks Automation, Inc. Stockholders' Equity	Noncontrolling Interests in Subsidiaries
Beginning Balance (in shares) at Sep. 30, 2013		80,039,104
Beginning Balance at Sep. 30, 2013	$ 632,656,000	$ 800,000	$ 1,825,499,000	$ 22,604,000	$ (1,015,991,000)	$ (200,956,000)	$ 631,956,000	$ 700,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under stock option, restricted stock and purchase plans, net (in shares)		336,673
Shares issued under stock option, restricted stock and purchase plans, net	390,000	$ 4,000	386,000				390,000
Stock-based compensation	11,062,000		11,062,000				11,062,000
Common stock dividend declared, at $0.40, $0.40 and $0.34 per share for fiscal years 2016, 2015 and 2014	(22,635,000)				(22,635,000)		(22,635,000)
Acquisition of noncontrolling interest	(3,189,000)		(2,328,000)				(2,328,000)	(861,000)
Comprehensive income (loss):
Net (loss) income	31,522,000				31,361,000		31,361,000	161,000
Foreign currency translation adjustments	(6,296,000)			(6,296,000)			(6,296,000)
Changes in unrealized gains (losses) on marketable securities, net of tax effects of $58, $(83) and $62 for fiscal years 2016, 2015 and 2014	(104,000)			(104,000)			(104,000)
Actuarial losses, net of tax effects of $161, $115 and $471 for fiscal years 2016, 2015 and 2014	(503,000)			(503,000)			(503,000)
Changes in unrealized losses on cash flow hedges, net of tax effects of $9	(14,000)						(14,000)
Ending Balance (in shares) at Sep. 30, 2014		80,375,777
Ending Balance at Sep. 30, 2014	642,889,000	$ 804,000	1,834,619,000	15,687,000	(1,007,265,000)	(200,956,000)	642,889,000	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under stock option, restricted stock and purchase plans, net (in shares)		717,275
Shares issued under stock option, restricted stock and purchase plans, net	(414,000)	$ 7,000	(421,000)				(414,000)
Stock-based compensation	12,159,000		12,159,000				12,159,000
Common stock dividend declared, at $0.40, $0.40 and $0.34 per share for fiscal years 2016, 2015 and 2014	(27,021,000)				(27,021,000)		(27,021,000)
Comprehensive income (loss):
Net (loss) income	14,221,000				14,221,000		14,221,000
Foreign currency translation adjustments	(9,557,000)			(9,557,000)			(9,557,000)
Changes in unrealized gains (losses) on marketable securities, net of tax effects of $58, $(83) and $62 for fiscal years 2016, 2015 and 2014	141,000			141,000			141,000
Actuarial losses, net of tax effects of $161, $115 and $471 for fiscal years 2016, 2015 and 2014	(605,000)			(605,000)			(605,000)
Recognition of pension settlement in earnings	232,000			232,000			232,000
Ending Balance (in shares) at Sep. 30, 2015		81,093,052
Ending Balance at Sep. 30, 2015	632,045,000	$ 811,000	1,846,357,000	5,898,000	(1,020,065,000)	(200,956,000)	632,045,000	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under stock option, restricted stock and purchase plans, net (in shares)		1,127,218
Shares issued under stock option, restricted stock and purchase plans, net	(2,381,000)	$ 10,000	(2,391,000)				(2,381,000)
Stock-based compensation	11,737,000		11,737,000				11,737,000
Common stock dividend declared, at $0.40, $0.40 and $0.34 per share for fiscal years 2016, 2015 and 2014	(27,503,000)				(27,503,000)		(27,503,000)
Comprehensive income (loss):
Net (loss) income	(69,476,000)				(69,476,000)		(69,476,000)
Foreign currency translation adjustments	8,844,000			8,844,000			8,844,000
Changes in unrealized gains (losses) on marketable securities, net of tax effects of $58, $(83) and $62 for fiscal years 2016, 2015 and 2014	(106,000)			(106,000)			(106,000)
Actuarial losses, net of tax effects of $161, $115 and $471 for fiscal years 2016, 2015 and 2014	(322,000)			(322,000)			(322,000)
Pension curtailment	852,000			852,000			852,000
Ending Balance (in shares) at Sep. 30, 2016		82,220,270
Ending Balance at Sep. 30, 2016	$ 553,690,000	$ 821,000	$ 1,855,703,000	$ 15,166,000	$ (1,117,044,000)	$ (200,956,000)	$ 553,690,000	$ 0