Organization of the Company and Basis of Presentation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Gross income required from sources that are itemized in the REIT tax laws to qualify as a REIT	For example, to qualify as a REIT, at least 95% of the Company’s gross income must come from sources that are itemized in the REIT tax laws.
Minimum percentage of REIT taxable income expected to distribute to stockholders	90.00%
Net operating loss carryforwards	$ 88
Non-Controlling Interests - Common OP Units	3,728,160	4,103,067	4,914,040