Equity Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Pre-tax compensation expense for unvested stock-based compensation grants	$ 5,200		$ 5,200
Service period applicable to the grantees on a weighted-average basis, years			1 year 3 months 18 days
RSUs vested and settled in shares of common stock, amount	$ 419	$ 563	$ 1,802	$ 2,505