Stock-Based Compensation Expense - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended		0 Months Ended	3 Months Ended		6 Months Ended		0 Months Ended	3 Months Ended		6 Months Ended		0 Months Ended											6 Months Ended		0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Feb. 16, 2012 Equity Incentive Plans	Jun. 30, 2014 Restricted Stock	Jun. 30, 2013 Restricted Stock	Jun. 30, 2014 Restricted Stock	Jun. 30, 2013 Restricted Stock	Dec. 27, 2012 2011 Equity Incentive Plan Installment	Jun. 30, 2014 Equity Awards	Jun. 30, 2013 Equity Awards	Jun. 30, 2014 Equity Awards	Jun. 30, 2013 Equity Awards	May 22, 2014 Non Employee Directors	May 09, 2013 Non Employee Directors	Feb. 16, 2012 Non Employee Directors	May 22, 2014 Non Employee Directors Restricted Class A Common Stock	May 09, 2013 Non Employee Directors Restricted Class A Common Stock	Feb. 16, 2012 Non Employee Directors Restricted Class A Common Stock	Feb. 16, 2012 Share-based Compensation Award, Tranche One Equity Incentive Plans	Dec. 27, 2012 Share-based Compensation Award, Tranche One 2011 Equity Incentive Plan Installment	Feb. 16, 2012 Share-based Compensation Award, Tranche Two Equity Incentive Plans	Dec. 27, 2012 Share-based Compensation Award, Tranche Two 2011 Equity Incentive Plan Installment	Feb. 16, 2012 Share-based Compensation Award, Tranche Three Equity Incentive Plans	Jun. 30, 2014 Minimum Restricted Stock	Jun. 30, 2014 Maximum Restricted Stock	Dec. 27, 2012 First And Second Anniversaries 2011 Equity Incentive Plan	Dec. 27, 2012 Third And Fourth Anniversaries 2011 Equity Incentive Plan
Share Based Compensation [Line Items]
Shares of time-vesting restricted Class A common stock																		93,312	168,540	161,724
Grant date fair value					$ 3,300,000			$ 1,700,000							$ 600,000	$ 600,000	$ 600,000
Cliff vesting term																		1 year	1 year	1 year
Time-vesting stock options to purchase					1,400,000.0
Exercise price					$ 4.34
Percentage of vesting stock based compensation																					30.00%		20.00%		20.00%
Number of stock options issued										800,000.0
Number of shares of Class A common stock										800,000.0
Grant date fair value										1,100,000
Exercise price per share										$ 4.34																$ 6.26	$ 7.74
Number of vesting period anniversaries										4												2		2
Award vesting percentage																												30.00%	20.00%
Number of stock options granted								400,000.0
Vesting stock based compensation related to awards	4,154,000	2,470,000	8,245,000	5,134,000							4,200,000	2,500,000	8,300,000	5,100,000
Unrecognized stock-based compensation expense											34,700,000		34,700,000
Weighted average remaining life for recognition of unrecognized compensation expense													2 years 10 months 24 days
Total Fair value of restricted stock awards vested						$ 1,100,000	$ 100,000	$ 2,100,000	$ 1,600,000
Stock options exercised			1,200,000	0