Equity Compensation - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Capitalization of stock-based compensation cost	$ 0	$ 0	$ 0	$ 0
Pre-tax compensation expense for unvested stock-based compensation grants	30,300		30,300
Service period applicable to the grantees on a weighted-average basis, years			2 years 110 days
Number of RSUs vested in the period that were settled in cash			48,935
RSUs vested and settled in cash, amount			3,073
Number of RSUs vested in the period that were settled in shares of common stock			68,103
RSUs vested and settled in shares of common stock, amount			$ 4,536