Supplemental Balance Sheet Information - Indefinite-Lived Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jan. 31, 2016	Jul. 31, 2016
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		$ 2.4
Accumulated impairment		(0.9)
Net carrying value		1.5
Foreign exchange		(0.2)
Balance, end of period		1.3
In-process research and development
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		2.2
Accumulated impairment		(0.9)
Net carrying value		1.3
In-process research and development | BLS | Spinoff
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value	$ 7.9
Net carrying value	3.6
Impairment losses	$ 4.3
Regulatory permits
Indefinite-lived Intangible Assets [Line Items]
Gross carrying value		0.2
Accumulated impairment		0.0
Net carrying value		$ 0.2