Term Receivable and Trade Accounts Receivable Balances (Detail) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2012	Jan. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade Accounts Receivable, Net	$ 404,783	$ 354,924
Term receivables, long-term	207,639	220,355
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade Accounts Receivable, Net	171,916	133,494
Term receivables, short-term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade Accounts Receivable, Net	$ 232,867	$ 221,430