Stockholders' Equity - Additional Information (Detail) (USD $)	1 Months Ended		6 Months Ended			6 Months Ended	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended
	May 23, 2013	Feb. 28, 2013	Jun. 30, 2013 Plans	Jun. 30, 2013 Restricted Stock [Member]	Dec. 31, 2012 Restricted Stock [Member]	Jun. 30, 2013 Performance Based Restricted Stock Unit [Member]	Jun. 30, 2013 Employee Stock Option [Member]	Jun. 30, 2012 Employee Stock Option [Member]	Jun. 30, 2013 Employee Stock Option [Member]	Jun. 30, 2012 Employee Stock Option [Member]	Jun. 30, 2013 Performance Based Stock Options [Member]	Jun. 30, 2013 Incentive Stock Options [Member]	Jun. 30, 2012 Incentive Stock Options [Member]	Jun. 30, 2013 Incentive Stock Options [Member]	Jun. 30, 2012 Incentive Stock Options [Member]	Jun. 30, 2013 Repurchase of Equity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option available for future grants			2,500,000
Number of stock based compensation plans			5
Stock incentive plan	1,600,000
Aggregate intrinsic value price per share				$ 8.52			$ 8.52		$ 8.52
Unrecognized stock-based compensation cost				$ 5,500,000			$ 500,000		$ 500,000
Weighted average period				28 months
Approximate units of performance restricted stock granted						139,000
Approximate units outstanding				1,060,128	582,212	225,000
Performance criteria met for approximate units				149,137		88,000
Options exercised, aggregate intrinsic value							2,300,000	900,000	3,900,000	900,000
Weighted average vesting period			11 months
Performance-based stock options Cumulative Granted											500,000
Performance-based stock options condition met											200,000
Unvested performance options											300,000
Fair value of Unvested performance options											$ 100,000
Incremental stock option expense												24,000	85,000
Total share-based compensation expense														63,000.0	200,000
Outstanding common stock repurchase program Authorized Amount		25,000,000
Shares repurchased			3,048,966
Additional stock repurchase program authorized amount			$ 25,000,000
Average cost of repurchase per share																$ 8.20
Stock repurchase program average price per share			$ 8.17