Stock Option Plan and Stock Grants - Additional Information (Detail) (USD $)	6 Months Ended			1 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jul. 03, 2012 Executive Compensation Contracts	May 08, 2012 Restricted Stock Directors Plan	Jan. 31, 2012 Restricted Stock Directors Plan	May 08, 2012 Restricted Stock Directors Plan Phase one	Jan. 31, 2012 Restricted Stock Directors Plan Phase one	May 08, 2012 Restricted Stock Directors Plan Phase two	Jan. 31, 2012 Restricted Stock Directors Plan Phase two	May 08, 2012 Restricted Stock Directors Plan Phase three	Jan. 31, 2012 Restricted Stock Directors Plan Phase three	Jan. 31, 2012 Restricted Stock Senior Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization of stock-related compensation	$ 3,285,000	$ 2,969,000
Share based compensation, grants awarded				16,000	31,000							60,332
Share based compensation, fair market value				1,100,000	2,200,000							4,200,000
Share based compensation, vesting description				One-third of the shares of restricted common stock covered by these awards vests on each of November 8, 2012, May 8, 2013, and May 8, 2014.	One-third of the shares of restricted common stock covered by these awards vests on each of December 31, 2012, December 31, 2013, and December 31, 2014.
Share based compensation, restricted stock, vesting date						Nov. 08, 2012	Dec. 31, 2012	May 08, 2013	Dec. 31, 2013	May 08, 2014	Dec. 31, 2014	Dec. 31, 2012
Compensation to be paid in cash to key employee over remainder of period			$ 1,400,000