Segment Information (Details) (USD $) In Thousands	3 Months Ended				6 Months Ended
	Jul. 31, 2011		Jul. 31, 2010		Jul. 31, 2011		Jul. 31, 2010		Jan. 31, 2011
Net sales to unaffiliated customers	$ 6,449,461		$ 5,473,961		$ 12,781,589		$ 11,095,016
Operating income	78,775		65,758		154,458		135,244
Stock-based compensation expense	(2,715)		(2,660)		(5,182)		(5,109)
Depreciation and amortization	14,187		10,793		28,943		21,948
Capital expenditures	12,004		8,287		19,047		14,295
Identifiable assets	6,197,066		5,496,130		6,197,066		5,496,130		6,488,292
Goodwill and acquisition-related intangible assets, net	125,583	[1]	40,896	[1]	125,583	[1]	40,896	[1]
Americas [Member]
Net sales to unaffiliated customers	2,697,655		2,598,618		5,313,460		5,061,331
Operating income	47,635		44,580		95,508		88,870
Depreciation and amortization	3,853		4,150		7,769		8,195
Capital expenditures	7,987		5,176		11,255		8,102
Identifiable assets	2,411,392		2,022,645		2,411,392		2,022,645
Goodwill and acquisition-related intangible assets, net	2,966	[1]	2,966	[1]	2,966	[1]	2,966	[1]
Europe [Member]
Net sales to unaffiliated customers	3,751,806		2,875,343		7,468,129		6,033,685
Operating income	33,855		23,838		64,132		51,483
Depreciation and amortization	10,334		6,643		21,174		13,753
Capital expenditures	4,017		3,111		7,792		6,193
Identifiable assets	3,785,674		3,473,485		3,785,674		3,473,485
Goodwill and acquisition-related intangible assets, net	$ 122,617	[1]	$ 37,930	[1]	$ 122,617	[1]	$ 37,930	[1]

[1] The increase in the goodwill and acquisition-related intangible assets, net, at July 31, 2011, is the result of the European acquisitions completed during the second semester of fiscal 2011.