Stock-Based Compensation - Additional Information (Detail) (USD $)	6 Months Ended		6 Months Ended				1 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 2010 Plan [Member]	Jun. 30, 2013 Amended 2010 Plan [Member]	Jun. 30, 2013 Restricted Stock [Member]	Jun. 30, 2013 Stock Options [Member] Minimum [Member]	Jun. 30, 2013 Stock Options [Member] Maximum [Member]	Jul. 31, 2013 Subsequent Event [Member]	Jul. 31, 2013 Subsequent Event [Member] Amended 2010 Plan [Member]	Jun. 30, 2013 Accelerated Stock Awards [Member]	Jun. 30, 2013 Accelerated Stock Awards [Member]	Jun. 30, 2013 Accelerated Stock Awards [Member] Awards granted on or prior to December 19, 2012 [Member]	Jun. 30, 2013 Accelerated Stock Awards [Member] Awards granted on or prior to December 19, 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock award compensation expense									$ 1,900,000	$ 5,900,000	$ 22,500,000	$ 22,500,000
Conversion ratio							3	0.333
Unamortized compensation costs	0
Number of shares authorized for grant		10,580,044	64,580,044
Maximum number of shares available for grants to each non-employee member			200,000
Stock options vesting period in years				3 years	3 years	4 years
Unamortized compensation related to restricted awards outstanding				$ 29,200,000
Cost of unvested awards expected to be recognized over a weighted average life, years				2 years 4 months 24 days
Number of Stock Options, Exercised (in shares)	0