Segment Information - Reportable Operating Segments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Segment Reporting Information
Revenues	$ 1,310.5	$ 1,257.1	$ 2,637.2	$ 2,525.5
Operating profit (loss)	51.0	11.8	74.8	25.4
Adjustment for income from unconsolidated affiliates, net, included in Aviation and Government Services	0.9	0.9	2.3	3.3
Income from unconsolidated affiliates, net	0.9	0.9	2.3	3.3
Interest expense	(3.0)	(2.4)	(6.3)	(5.1)
Income from continuing operations before income taxes	48.9	10.3	70.9	23.6
Corporate
Segment Reporting Information
Operating profit (loss)	(36.4)	(40.3)	(71.0)	(75.5)
Segment Reconciling Items
Segment Reporting Information
Adjustment for income from unconsolidated affiliates, net, included in Aviation and Government Services	(1.1)	(0.8)	(2.4)	(3.3)
Adjustment for tax deductions for energy efficient government buildings, included in Technical Solutions	(0.8)	(0.9)	(1.4)	(1.1)
Income from unconsolidated affiliates, net	(1.1)	(0.8)	(2.4)	(3.3)
Business & Industry | Operating Segments
Segment Reporting Information
Revenues	732.6	730.4	1,487.6	1,474.0
Operating profit (loss)	41.0	32.6	73.4	61.0
Aviation | Operating Segments
Segment Reporting Information
Revenues	232.2	203.0	464.2	406.8
Operating profit (loss)	7.6	5.5	13.0	9.4
Emerging Industries Group | Operating Segments
Segment Reporting Information
Revenues	192.0	195.0	392.6	394.1
Operating profit (loss)	12.0	12.9	24.4	27.8
Technical Solutions | Operating Segments
Segment Reporting Information
Revenues	110.8	100.9	218.5	194.4
Operating profit (loss)	10.6	4.3	18.8	8.3
Government Services | Operating Segments
Segment Reporting Information
Revenues	42.9	27.7	74.3	56.2
Operating profit (loss)	$ 18.2	$ (1.5)	$ 20.0	$ (1.3)