Segment Information - Financial Information for Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2015
Revenue
Product	$ 111,596	$ 120,816	$ 302,238	$ 336,941
Services	35,938	24,078	100,532	70,002
Total revenue	147,534	144,894	402,770	406,943
Gross profit	54,163	51,187	141,517	136,300
Segment operating income (loss)	8,494	10,170	(6,165)	6,743
Total assets	682,321		682,321		$ 759,654
Brooks Semiconductor Solutions Group
Revenue
Product	99,254	108,687	268,671	298,737
Services	19,179	19,399	57,657	57,197
Total revenue	118,433	128,086	326,328	355,934
Gross profit	42,904	46,515	114,506	122,938
Segment operating income (loss)	13,119	17,162	22,717	31,280
Total assets	326,083		326,083		317,069
Brooks Life Science Systems
Revenue
Product	12,342	12,129	33,567	38,204
Services	16,759	4,679	42,875	12,805
Total revenue	29,101	16,808	76,442	51,009
Gross profit	11,259	4,672	27,011	13,362
Segment operating income (loss)	(736)	(4,656)	(7,555)	(14,563)
Total assets	249,638		249,638		110,910
Operating Segments
Revenue
Product	111,596	120,816	302,238	336,941
Services	35,938	24,078	100,532	70,002
Total revenue	147,534	144,894	402,770	406,943
Gross profit	54,163	51,187	141,517	136,300
Segment operating income (loss)	12,383	$ 12,506	15,162	$ 16,717
Total assets	$ 575,721		$ 575,721		$ 427,979