Restructuring and Related Costs - Cumulative Restructuring and Related Charges (Details) $ in Millions	Jul. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Cumulative charges	$ 86.7
GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	19.6
2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	67.1
External Support Fees
Restructuring Cost and Reserve [Line Items]
Cumulative charges	32.0
External Support Fees | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	2.0
External Support Fees | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	30.0
Employee Severance
Restructuring Cost and Reserve [Line Items]
Cumulative charges	26.3
Employee Severance | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	12.8
Employee Severance | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	13.5
Other Project Fees
Restructuring Cost and Reserve [Line Items]
Cumulative charges	15.5
Other Project Fees | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	4.9
Other Project Fees | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	10.7
Lease Exit
Restructuring Cost and Reserve [Line Items]
Cumulative charges	7.7
Lease Exit | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	0.0
Lease Exit | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	7.7
Asset Impairment
Restructuring Cost and Reserve [Line Items]
Cumulative charges	5.2
Asset Impairment | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	0.0
Asset Impairment | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	$ 5.2