Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Apr. 30, 2012	Jan. 31, 2012
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 11,755	$ 12,202
Common stock, par value	$ 0.10	$ 0.10
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	220,306,639	219,708,779
Common stock, shares outstanding	219,045,829	218,636,842
Treasury stock, shares	1,260,810	1,071,937