Stock Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended			12 Months Ended							3 Months Ended		6 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 25% of the shares issued	Dec. 31, 2013 25% of the shares issued	Dec. 31, 2012 25% of the shares issued	Dec. 31, 2011 25% of the shares issued	Dec. 31, 2010 25% of the shares issued	Dec. 31, 2009 Non-Employee Directors	Dec. 31, 2008 Non-Employee Directors	Dec. 31, 2007 Non-Employee Directors	Jun. 30, 2014 Employee Stock Option	Jun. 30, 2013 Employee Stock Option	Jun. 30, 2014 Employee Stock Option	Jun. 01, 2006 Employee Stock Option	Jun. 30, 2014 Employee Stock Option Maximum
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Common stock reserved for issuance																8,000,000
Options granted vesting period															4 years		10 years
Stock option issued													0	0
Restricted stock-based compensation expense	$ 1,587,000	$ 1,155,000	$ 3,013,000	$ 2,167,000
Incentive restricted stock issued					86,284	93,528	108,828	91,364	209,358	12,224	80,676	14,464
Shares granted exercise price					$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Percentage of shares vested					25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%
Restricted stock, unrecognized stock-based compensation cost	$ 15,900,000		$ 15,900,000
Restricted stock, weighted-average remaining requisite service period			2 years 9 months 18 days