CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Oct. 31, 2015	Jan. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	139,977,240	139,559,000
Common stock, shares outstanding	83,773,648	85,323,154
Treasury stock, shares	56,203,592	54,235,846