Segment Information - Company's Segments Information (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2019	Apr. 30, 2018
Net sales:
Net sales	$ 1,003.1	$ 1,033.2
Earnings (losses) from operations:
Earnings from operations for segments	209.6	249.8
Americas
Net sales:
Net sales	406.3	425.3
Earnings (losses) from operations:
Earnings from operations for segments	56.8	74.9
Asia-Pacific
Net sales:
Net sales	324.1	328.6
Earnings (losses) from operations:
Earnings from operations for segments	86.0	100.1
Japan
Net sales:
Net sales	144.7	150.6
Earnings (losses) from operations:
Earnings from operations for segments	53.4	58.3
Europe
Net sales:
Net sales	102.5	107.0
Earnings (losses) from operations:
Earnings from operations for segments	12.2	14.2
Total reportable segments
Net sales:
Net sales	977.6	1,011.5
Earnings (losses) from operations:
Earnings from operations for segments	208.4	247.5
Other
Net sales:
Net sales	25.5	21.7
Earnings (losses) from operations:
Earnings from operations for segments	$ 1.2	$ 2.3