Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2012 Y M
Summary Of Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	100.00%
Expected lease-up periods for estimating lost rentals, in months	6
Percentage of ordinary taxable income to be distributed for real estate investment trust qualification	90.00%
Number of years of federal income tax at corporate rates on failure to qualify as REIT	4
Maximum
Summary Of Significant Accounting Policies [Line Items]
Stock award vesting period in years, maximum	10 years
Time-Based Awards | Minimum
Summary Of Significant Accounting Policies [Line Items]
Stock award vesting period in years, maximum	3 years
Time-Based Awards | Maximum
Summary Of Significant Accounting Policies [Line Items]
Stock award vesting period in years, maximum	7 years
Market Conditions Based Awards | Minimum
Summary Of Significant Accounting Policies [Line Items]
Stock award vesting period in years, maximum	3 years
Market Conditions Based Awards | Maximum
Summary Of Significant Accounting Policies [Line Items]
Stock award vesting period in years, maximum	7 years