Equity Based Compensation - Summary of Shares Available for Issuance Under Restricted Stock Plan (Detail) (USD $)			3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 2009 Grants [Member]	Mar. 31, 2013 2009 Forfeitures [Member]	Mar. 31, 2013 2010 Grants [Member]	Mar. 31, 2013 2010 Forfeitures [Member]	Mar. 31, 2013 2011 Grants [Member]	Mar. 31, 2013 2011 Forfeitures [Member]	Mar. 31, 2013 2012 Grants [Member]	Mar. 31, 2013 2012 Forfeitures [Member]	Mar. 31, 2013 2013 Grants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under the 2008 Restricted Stock Plan	2,782	62,500
Shares of restricted stock, Grants			(13,761)		(4,625)		(17,033)		(19,967)		(8,407)
Shares of restricted stock, Forfeitures				2,500		700		525		350
Remaining shares available for issuance at March 31, 2013	2,782	62,500
Weighted-average grant date fair value per share, Grants			$ 142.50		$ 10.40		$ 10.40		$ 5.51		$ 8.33
Weighted-average grant date fair value per share, Forfeitures				$ 168.00		$ 168.00		$ 168.00		$ 168.00