Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data	Apr. 30, 2011	Jan. 31, 2011
Trade accounts receivable, allowance for doubtful accounts	$ 3,780	$ 3,941
Property, plant, and equipment, accumulated depreciation	268,000	257,576
Intangible assets, accumulated amortizaton	$ 161,448	$ 156,481
Common stock, no par value	$ 0	$ 0
Common stock, shares authorized	300,000	300,000
Common stock, shares issued	110,870	111,249
Common stock, shares outstanding	110,870	111,249
Incentive stock, no par value	$ 0	$ 0
Incentive stock, shares authorized	1,200	1,200
Incentive stock, issued	0	0