Equity Based Compensation - Summary of Shares Available for Issuance Under Restricted Stock Plan (Detail) (USD $)			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 2009 Grants [Member]	Sep. 30, 2012 2009 Forfeitures [Member]	Sep. 30, 2012 2010 Grants [Member]	Sep. 30, 2012 2010 Forfeitures [Member]	Sep. 30, 2012 2011 Grants [Member]	Sep. 30, 2012 2011 Forfeitures [Member]	Sep. 30, 2012 2012 Grants [Member]	Sep. 30, 2012 2012 Forfeitures [Member]	Sep. 30, 2012 Restricted stock [Member] 2009 Grants [Member]	Sep. 30, 2012 Restricted stock [Member] 2009 Forfeitures [Member]	Sep. 30, 2012 Restricted stock [Member] 2010 Grants [Member]	Sep. 30, 2012 Restricted stock [Member] 2010 Forfeitures [Member]	Sep. 30, 2012 Restricted stock [Member] 2011 Grants [Member]	Sep. 30, 2012 Restricted stock [Member] 2011 Forfeitures [Member]	Sep. 30, 2012 Restricted stock [Member] 2012 Grants [Member]	Sep. 30, 2012 Restricted stock [Member] 2012 Forfeitures [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under the 2008 Restricted Stock Plan	13,543	62,500
Shares of restricted stock, Grants			(13,761)		(4,625)		(17,033)		(17,613)
Shares of restricted stock, Forfeitures				2,500		700		525		350
Remaining shares available for issuance at September 30, 2012	13,543	62,500
Shares of restricted stock, Grants											$ 142.50		$ 10.40		$ 10.40		$ 5.11
Shares of restricted stock, Forfeitures												$ 168.00		$ 168.00		$ 168.00		$ 168.00