Indebtedness - Summary of Indebtedness at Estimated Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Debt Disclosure [Abstract]
Mortgage Loans Payable, Net, Carrying Amount	$ 577,453		$ 580,215
Senior Unsecured Notes, Carrying Amount	446,326		445,916
Unsecured Term Loan, Carrying Amount	200,000		0
Unsecured Credit Facility, Carrying Amount	52,000	[1]	173,000	[1]
Total, Carrying Amount	1,275,779		1,199,131
Mortgage Loans Payable, Net, Fair Value	606,014		585,449
Senior Unsecured Notes, Net, Fair Value	485,040		482,781
Unsecured Term Loan, Fair Value	200,000
Unsecured Credit Facility, Fair Value	52,088		173,000
Total, Fair Value	$ 1,343,142		$ 1,241,230

[1] * The maturity date may be extended an additional year at our election, subject to certain restrictions.