Earnings (Loss) Per Share - Computation of Basic and Diluted Earnings Per Common Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Allocation of net (loss) income to common stockholders-basic and diluted	$ 24,579	$ (1,967)	$ (26,164)	$ 1,542
Net loss available to common shareholders	24,579	(25,482)	(26,164)	(40,552)
Common stock:
Basic	64,732,730	6,062,664	60,265,132	6,054,360
Diluted	66,635,484	6,062,664	60,265,132	6,054,360
Common stock:
Basic	$ 0.38	$ (4.20)	$ (0.43)	$ (6.70)
Diluted	$ 0.37	$ (4.20)	$ (0.43)	$ (6.70)
Common Stock Class L [Member]
Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Allocation of net (loss) income to common stockholders-basic and diluted		19,589		38,102
Weighted average number of common shares:
Weighted average number of common shares: Class L-basic and diluted		1,327,115		1,325,297
Earnings (loss) per common share:
Earnings (loss) per common share-basic and diluted: Class L-basic and diluted		$ 14.76		$ 28.75
Common Stock Class L [Member] | Nonvested [Member]
Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Accretion of Class L preference		19,589		38,102
Common Stock Class L [Member] | Vested [Member]
Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Accretion of Class L preference		3,926		3,992
Common Stock Class A [Member]
Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Allocation of net (loss) income to common stockholders-basic and diluted	$ 24,579	$ (25,482)	$ (26,164)	$ (40,552)