Segment Information - Company's Segments Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Net sales:
Net sales	$ 976.2	$ 949.3	$ 2,835.4	$ 2,772.2
Earnings from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	203.7	192.1	616.6	580.1
Americas [Member]
Net sales:
Net sales	421.4	417.1	1,251.7	1,254.5
Earnings from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	67.7	65.0	223.2	215.8
Asia-Pacific [Member]
Net sales:
Net sales	283.2	246.7	775.2	715.3
Earnings from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	74.9	63.0	204.8	178.7
Japan [Member]
Net sales:
Net sales	138.7	150.1	406.8	419.2
Earnings from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	46.0	47.8	134.5	137.4
Europe [Member]
Net sales:
Net sales	109.7	104.3	317.9	312.0
Earnings from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	13.7	14.8	47.9	43.5
Reportable Geographical Components [Member]
Net sales:
Net sales	953.0	918.2	2,751.6	2,701.0
Earnings from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	202.3	190.6	610.4	575.4
Other [Member]
Net sales:
Net sales	23.2	31.1	83.8	71.2
Earnings from operations:
Segment Reporting Earnings Losses From Continuing Operations Before Unallocated Corporate Expenses Interest	$ 1.4	$ 1.5	$ 6.2	$ 4.7