Segment Information - Reconciliation of Segments' Earnings from Operations to Company's Consolidated Earnings from Operations Before Income Taxes (Detail) (USD $)	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Segment Reporting [Abstract]
Earnings from operations for segments	$ 934,570,000	$ 823,638,000	$ 878,910,000
Unallocated corporate expenses	(140,651,000)	(126,421,000)	(127,765,000)
Interest expense, financing costs and other income, net	(49,463,000)	(53,641,000)	(43,475,000)
Other operating expense	(489,590,000)	0	(42,719,000)
Earnings from operations before income taxes	$ 254,866,000	$ 643,576,000	$ 664,951,000