Condensed Consolidated Statements of Comprehensive Earnings (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011
Condensed Consolidated Statements of Comprehensive Earnings [Abstract]
Net earnings	$ 91,801	$ 90,043	$ 173,335	$ 171,106
Foreign currency translation adjustments	(20,967)	4,942	(21,353)	35,016
Unrealized gain (loss) on marketable securities	5	(971)	1,102	475
Less: Reclassification adjustment for loss included in net earnings		53		53
Unrealized gain (loss) on marketable securities	5	(918)	1,102	528
Unrealized loss on hedging instruments	(27,582)	(9,528)	(30,371)	(8,146)
Less: reclassification adjustment for loss included in net earnings	4,013	734	7,763	970
Unrealized loss on hedging instruments	(23,569)	(8,794)	(22,608)	(7,176)
Amortization of net loss	3,907	1,269	7,993	2,586
Amortization of prior service cost	89	102	178	203
Net unrealized gain on benefit plans	3,996	1,371	8,171	2,789
Other comprehensive (loss) earnings, before tax	(40,535)	(3,399)	(34,688)	31,157
Income tax benefit related to items of other comprehensive (loss) earnings	6,691	4,325	6,516	2,257
Other comprehensive (loss) earnings, net of tax	(33,844)	926	(28,172)	33,414
Comprehensive earnings	$ 57,957	$ 90,969	$ 145,163	$ 204,520