Segment Information - Financial Information for Business Segments - Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Revenue
Revenue	$ 179,368	$ 142,599
Gross profit	72,081	54,259
Segment operating income (loss)	5,333	4,925
Products
Revenue
Revenue	141,732	105,772
Services
Revenue
Revenue	37,636	36,827
Brooks Semiconductor Solutions Group
Revenue
Revenue	112,707	95,157
Gross profit	45,915	38,494
Brooks Semiconductor Solutions Group \| Products
Revenue
Revenue	101,801	83,791
Brooks Semiconductor Solutions Group \| Services
Revenue
Revenue	10,906	11,366
Brooks Life Sciences
Revenue
Revenue	66,661	47,442
Gross profit	26,166	15,765
Brooks Life Sciences \| Products
Revenue
Revenue	39,931	21,981
Brooks Life Sciences \| Services
Revenue
Revenue	26,730	25,461
Operating Segments
Revenue
Segment operating income (loss)	17,731	10,322
Depreciation expense	3,687	2,545
Operating Segments \| Brooks Semiconductor Solutions Group
Revenue
Segment operating income (loss)	16,141	11,718
Depreciation expense	916	996
Operating Segments \| Brooks Life Sciences
Revenue
Segment operating income (loss)	1,590	(1,396)
Depreciation expense	$ 2,771	$ 1,549

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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