Segment Information - Company's Segments Information (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
Net sales:
Net sales	$ 1,033.2	$ 899.6
Earnings (losses) from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	249.8	195.0
Americas [Member]
Net sales:
Net sales	425.3	391.7
Earnings (losses) from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	74.9	62.4
Asia-Pacific [Member]
Net sales:
Net sales	328.6	257.3
Earnings (losses) from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	100.1	73.1
Japan [Member]
Net sales:
Net sales	150.6	128.4
Earnings (losses) from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	58.3	42.8
Europe [Member]
Net sales:
Net sales	107.0	94.6
Earnings (losses) from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	14.2	13.6
Reportable Geographical Components [Member]
Net sales:
Net sales	1,011.5	872.0
Earnings (losses) from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	247.5	191.9
Other [Member]
Net sales:
Net sales	21.7	27.6
Earnings (losses) from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	$ 2.3	$ 3.1