Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Income Statement [Abstract]
Revenues	$ 1,496.0	$ 1,594.7	$ 3,109.0	$ 3,202.6
Operating expenses	1,306.1	1,414.2	2,739.9	2,860.2
Selling, general and administrative expenses	119.4	108.4	237.0	221.1
Restructuring and related expenses	1.8	2.7	5.0	6.5
Amortization of intangible assets	12.5	14.8	25.1	30.0
Impairment loss	172.8	0.0	172.8	0.0
Operating (loss) profit	(116.7)	54.5	(70.8)	84.8
Income from unconsolidated affiliates	0.9	0.8	1.8	1.7
Interest expense	(10.5)	(12.8)	(20.7)	(26.3)
(Loss) income from continuing operations before income taxes	(126.2)	42.5	(89.7)	60.2
Income tax provision	(10.6)	(12.6)	(19.2)	(17.3)
(Loss) income from continuing operations	(136.8)	29.9	(108.9)	42.9
(Loss) income from discontinued operations, net of taxes	0.0	(0.2)	0.1	(0.2)
Net (loss) income	(136.8)	29.7	(108.8)	42.7
Other comprehensive (loss) income
Interest rate swaps	(8.7)	(3.5)	(9.9)	(12.2)
Foreign currency translation	(4.2)	(0.9)	(3.8)	2.2
Income tax benefit	2.4	1.0	2.7	3.3
Comprehensive (loss) income	$ (147.3)	$ 26.3	$ (119.8)	$ 36.0
Net (loss) income per common share — Basic
(Loss) income from continuing operations (in usd per share)	$ (2.05)	$ 0.45	$ (1.63)	$ 0.65
(Loss) income from discontinued operations (in usd per share)	0	0	0	0
Net (loss) income (in usd per share)	(2.05)	0.45	(1.63)	0.64
Net (loss) income per common share — Diluted
(Loss) income from continuing operations (in usd per share)	(2.05)	0.45	(1.63)	0.64
(Loss) income from discontinued operations (in usd per share)	0	0	0	0
Net (loss) income (in usd per share)	$ (2.05)	$ 0.45	$ (1.63)	$ 0.64
Weighted-average common and common equivalent shares outstanding
Basic (in shares)	66.9	66.5	66.9	66.4
Diluted (in shares)	66.9	66.8	66.9	66.7