Commitment and Contingencies - Future Minimum Rental Payments Under Terms of all Non-Cancelable Ground and Operating Leases (Parenthetical) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012
Contractual Obligation Fiscal Year Maturity [Line Items]
Minimum rental payments have not been reduced by minimum sublease rentals due in the future under non-cancelable subleases.	$ 8,339