Business Segment Information - Reconciliation of Segment Adjusted EBITDA to Net Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Segment Reporting Information [Line Items]
Interest expense, net	$ (8.4)			$ (6.8)			$ (24.2)	$ (18.3)
(Provision) benefit for income taxes	(1.9)			(3.8)			0.0	7.2
Restructuring costs	(1.3)			(0.9)			(4.2)	(6.9)
Stock-based compensation expense							(7.3)	(5.1)
Impairment charges							(2.8)
Net income (loss)	5.6	$ 5.6	$ (14.6)	18.3	$ 7.4	$ 9.4	(3.3)	35.1
Fire & Emergency [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	12.1			25.3			35.8	65.5
Commercial [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	19.4			11.8			39.7	25.7
Recreation [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	12.8			17.9			39.4	38.7
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	(10.8)			(7.4)			(32.2)	(25.6)
Operating Segment [Member] | Fire & Emergency [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	12.1			25.3			35.8	65.5
Operating Segment [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	19.4			11.8			39.7	25.7
Operating Segment [Member] | Recreation [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	12.8			17.9			39.4	38.7
Reconciling Items [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	(10.9)			(11.7)			(34.8)	(33.9)
Interest expense, net	(8.4)			(6.8)			(24.2)	(18.3)
(Provision) benefit for income taxes	(1.9)			(3.8)				7.2
Transaction expenses	(0.5)						(0.7)	(2.1)
Sponsor expense reimbursement				(0.2)			(0.6)	(0.5)
Restructuring costs	(1.3)			(0.9)			(4.2)	(6.9)
Stock-based compensation expense	(2.5)			(1.4)			(7.3)	(5.1)
Non-cash purchase accounting expense				(0.5)				(1.2)
Legal matters	(0.8)			(1.1)			(5.3)	(2.8)
Impairment charges							(2.8)
Losses attributable to assets held for sale	(1.0)						(3.3)
Deferred purchase price payment	$ (0.6)			(1.9)			$ (2.8)	(4.1)
First year public company costs				$ (1.0)				$ (1.5)