Share-Based Compensation - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2014	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Amended and Restated 2012 Long Term Incentive Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Grant period				10 years
Authorized shares for issuance		5,550,000		5,550,000
Number of stock options granted to employees		154,000	469,500	663,000	1,835,500
Vesting period				4 years
Number of shares available for grant		2,913,500		2,913,500
Options outstanding		2,579,324.000		2,579,324.000		1,973,500
Weighted average exercise price		$ 12.95		$ 12.95		$ 7.50
Additional shares authorized	2,900,000
Unearned share-based compensation estimated to be expense through 2017		$ 18,100,000		$ 18,100,000
Recognition period of unearned share-based compensation				2 years 11 months 1 day
Consultant [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share Based Compensation Nonemployee		$ 26,000	$ 63,000	$ 72,000	$ 63,000