Segment Information - Company's Segments Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2013	Apr. 30, 2012
Net sales:
Net sales	$ 895,484	$ 819,170
Earnings (losses) from operations:
Earnings (losses) from operations	182,962	164,435
Americas [Member]
Net sales:
Net sales	407,697	385,674
Earnings (losses) from operations:
Earnings (losses) from operations	58,962	55,941
Asia-Pacific [Member]
Net sales:
Net sales	223,427	195,070
Earnings (losses) from operations:
Earnings (losses) from operations	55,459	51,060
Japan [Member]
Net sales:
Net sales	144,527	141,789
Earnings (losses) from operations:
Earnings (losses) from operations	53,419	42,560
Europe [Member]
Net sales:
Net sales	92,986	87,907
Earnings (losses) from operations:
Earnings (losses) from operations	14,278	16,655
Total reportable segments [Member]
Net sales:
Net sales	868,637	810,440
Earnings (losses) from operations:
Earnings (losses) from operations	182,118	166,216
Other [Member]
Net sales:
Net sales	26,847	8,730
Earnings (losses) from operations:
Earnings (losses) from operations	$ 844	$ (1,781)