Stockholders' Equity - Additional Information (Detail) (USD $)	1 Months Ended		12 Months Ended
	Dec. 30, 2010	Jul. 31, 2006	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011	Sep. 30, 2011
Stockholders Equity [Line Items]
Common stock, shares, repurchase program						2,000,000
Repurchases of common stock				125,000
Repurchases of stock, value				$ 2,929,000
Share repurchase description			The Company's new credit agreement prohibits the repurchase of shares until February 2014, after which repurchases may be made subject to compliance with certain covenants.
Shares available for grant			967,057
Expected dividend yield			0.00%	0.00%	0.00%
Weighted average remaining term for stock options outstanding			6 years 1 month 6 days
Aggregate intrinsic value for stock options outstanding			5,800,000
Aggregate intrinsic value for stock options exercisable			4,300,000
Proceeds from exercise of stock options			1,400,000	600,000
Intrinsic value of stock options exercised			2,600,000	1,400,000
Unrecognized stock compensation related to unvested option awards			1,700,000
Expected date through which unrecognized stock compensation is recognized			Jan. 31, 2017
Weighted average grant date fair value			$ 12.06	$ 12.97	$ 18.01
Unrecognized stock compensation related to restricted stock units			21,400,000	16,000,000
Term of warrants		5 years
Shares of common stock to be purchased for warrant rights		375,000
Exercise price of warrants		$ 11.00
Proceeds from exercise of stock warrants	4,100,000				4,129,000
Maximum
Stockholders Equity [Line Items]
Term of option awards			10 years
Restricted Stock Units (RSUs)
Stockholders Equity [Line Items]
Recognized compensation expense			7,000,000	4,400,000
Restricted Stock Units (RSUs) | Maximum
Stockholders Equity [Line Items]
Vesting period of awards			5 years
Restricted Stock Units (RSUs) | Minimum
Stockholders Equity [Line Items]
Vesting period of awards			3 years
Stock Options
Stockholders Equity [Line Items]
Recognized compensation expense			$ 700,000	$ 800,000