Segment Information - Company's Segments Information (Details) - USD ($) $ in Millions		3 Months Ended
		Apr. 30, 2020	Apr. 30, 2019
Net sales:
Net sales		$ 555.5	$ 1,003.1
Earnings (losses) from operations:
(Loss) earnings from operations for segments	[1]	(24.0)	209.6
Americas
Net sales:
Net sales		225.1	406.3
Earnings (losses) from operations:
(Loss) earnings from operations for segments	[1]	(41.2)	56.8
Asia-Pacific
Net sales:
Net sales		173.7	324.1
Earnings (losses) from operations:
(Loss) earnings from operations for segments	[1]	15.9	86.0
Japan
Net sales:
Net sales		86.3	144.7
Earnings (losses) from operations:
(Loss) earnings from operations for segments	[1]	16.4	53.4
Europe
Net sales:
Net sales		61.3	102.5
Earnings (losses) from operations:
(Loss) earnings from operations for segments	[1]	(10.0)	12.2
Total reportable segments
Net sales:
Net sales		546.4	977.6
Earnings (losses) from operations:
(Loss) earnings from operations for segments	[1]	(18.9)	208.4
Other
Net sales:
Net sales		9.1	25.5
Earnings (losses) from operations:
(Loss) earnings from operations for segments	[1]	$ (5.1)	$ 1.2

[1] Represents earnings from operations before (i) unallocated corporate expenses, (ii) Interest expense and financing costs and (iii) Other income, net.