Stock Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended				12 Months Ended		12 Months Ended				12 Months Ended	1 Months Ended		12 Months Ended			1 Months Ended		3 Months Ended
	Feb. 02, 2013	Feb. 02, 2013 One-time charge	Feb. 02, 2013 Stock Option Plan 2007	Feb. 02, 2013 Stock Option Plan 2007 Employees, Consultants and Directors	Feb. 02, 2013 Stock Option Plan 2007 Maximum	Feb. 02, 2013 Stock Incentive Plan 2012	Jan. 29, 2011 Out of The Money Stock Options Shareholder	Jan. 29, 2011 Out of The Money Stock Options Original Exercise Price Maximum	Jan. 29, 2011 Out of The Money Stock Options Original Exercise Price Minimum	Jan. 29, 2011 Out of The Money Stock Options Granted On April 20, 2009	Feb. 02, 2013 After Employee Terminated Stock Option Plan 2007 Minimum	May 04, 2012 Restricted Stock Stock Incentive Plan 2012 Installment	May 04, 2012 Stock Options Stock Incentive Plan 2012	Feb. 02, 2013 Stock Options Stock Incentive Plan 2012 Installment	Feb. 02, 2013 Stock Options Stock Incentive Plan 2012 Maximum	Feb. 02, 2013 Stock Options Stock Incentive Plan 2012 Minimum	May 03, 2012 IPO Stock Option Plan 2007	May 03, 2012 IPO Stock Option Plan 2007 One-time charge	Jul. 28, 2012 IPO Stock Option Plan 2007 One-time charge
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares authorized				1,600,000		2,913,900
Vesting period (in years)			4 years
Term of options					10 years						30 days
Options granted	730,500		0										650,500	80,000
Number of stock options repriced							739,500
Exercise price of options							$ 8.98	$ 14.47	$ 9.64	$ 6.45			$ 15.50		$ 18.37	$ 15.72
Number of optionees affected from re-pricing							48
Incremental unrecognized stock-based compensation expense							$ 600,000
Stock-based compensation expense	9,570,000	7,600,000																7,600,000	7,600,000
Increase in deferred tax assets and income tax payable																	3,000,000
Share-based compensation arrangement by share-based payment award, award vest												2		4
Fair value of stock option granted														6,600,000
Stock options granted, grant date fair value per share	$ 15.60														$ 9.65	$ 7.69
Weighted average recognition period	2 years 8 months 12 days											2 years		4 years
Restricted shares of Class A common stock granted												5,161
Restricted shares of Class A common stock granted, grant date fair value												300,000
Shares available for issuance						2,167,434
Total unrecognized stock-based compensation expense related to untested stock options and restricted stock grants	$ 5,800,000