Fair Value of Financial Instruments - Non-Financial Assets Measured at Fair Value on a Non-Recurring Basis (Details) - USD ($)	3 Months Ended	9 Months Ended
	Jul. 31, 2020	Jul. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, impairment loss	$ 0	$ 163,800,000
Impairment of intangible assets	$ 0
Education
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, impairment loss		99,300,000
Aviation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, impairment loss		55,500,000
Impairment of intangible assets		5,600,000
Impairment of intangible assets, gross		(13,800,000)
Impairment of intangible assets, accumulated amortization		8,200,000
Technical Solutions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, impairment loss		9,000,000.0
Impairment of intangible assets		3,400,000
Impairment of intangible assets, gross		(8,700,000)
Impairment of intangible assets, accumulated amortization		$ 5,300,000