CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 14,221	$ 31,522	$ (2,150)
Change in cumulative foreign currency translation adjustments, net of tax effects of $21, ($580), and $376 for fiscal years 2015, 2014 and 2013	(9,557)	(6,296)	(2,113)
Change in unrealized gains (losses) on available for sale securities, net of tax effects of $(83), $62, and $79 for fiscal years 2015, 2014 and 2013	141	(104)	(135)
Change in fair value of cash flow hedges, net of tax impact of $9 and ($9) for fiscal years 2014 and 2013	0	(14)	14
Actuarial (losses) gains, net of tax effects of $115, $471, and ($360) for fiscal years 2015, 2014 and 2013	(605)	(503)	1,109
Pension settlement	232	0	87
Comprehensive income (loss), net of tax	4,432	24,605	(3,188)
Comprehensive income attributable to noncontrolling interests	0	(161)	(65)
Comprehensive income (loss) attributable to Brooks Automation, Inc., net of tax	$ 4,432	$ 24,444	$ (3,253)