Segment Information (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Reconciliation of segments earnings from continuing operations to Company's consolidated earnings from continuing operations before income taxes
Earnings from operations for segments	$ 175,621	$ 133,866	$ 558,426	$ 409,101
Unallocated corporate expenses	(29,444)	(29,867)	(93,024)	(81,274)
Interest and other expenses, net	(10,393)	(12,997)	(30,159)	(36,256)
Other expense		(6,421)	(42,719)	(11,226)
Earnings from operations before income taxes	$ 135,784	$ 84,581	$ 392,524	$ 280,345