Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2011

Fair Value Measurements/Fair Value of Financial Instruments [Abstract]

Fair Value of Financial Instruments

15. Fair Value of Financial Instruments

The estimated fair values of financial instruments have been determined by us using available market information and appropriate valuation methods. Considerable judgment is required in interpreting market data to develop the estimates of fair value. Accordingly, the estimates presented herein are not necessarily indicative of the amounts that we could realize in a current market exchange. The use of different market assumptions and/or estimation methods may have a material effect on the estimated fair value amounts. We have used the following market assumptions and/or estimation methods:

Cash and Cash Equivalents and Accounts and Other Receivables - The carrying amounts reported in the balance sheets for these financial instruments approximate fair value because of their short maturities.

Notes Receivable — The fair value is estimated by using the current interest rates at which similar loans would be made. The carrying amounts reported in the balance sheets approximate fair value.

Mortgage Notes Payable — The fair value estimated at June 30, 2011 and December 31, 2010 was $721.4 million and $573.5 million, respectively, calculated based on the net present value of payments over the term of the loans using estimated market rates for similar mortgage loans and remaining terms. The carrying amount of these notes was approximately $644.2 million and $514.5 million at June 30, 2011 and December 31, 2010, respectively.

Unsecured Senior Notes Payable — The fair value estimated at June 30, 2011 and December 31, 2010 was $732.0 million and $712.4 million, calculated based on the net present value of payments over the terms of the notes using estimated market rates for similar notes and remaining terms. The carrying amount of these notes was approximately $688.6 million and $688.4 million at June 30, 2011 and December 31, 2010, respectively.

The fair market value calculation of our debt, for the period ended June 30, 2011, includes assumptions as to the effects that prevailing market conditions would have on existing secured or unsecured debt. The calculation uses a market rate spread over the risk free interest rate. This spread is determined by using the weighted average life to maturity coupled with loan-to-value considerations of the respective debt. Once determined, this market rate is used to discount the remaining debt service payments in an attempt to reflect the present value of this stream of cash flows. While the determination of the appropriate market rate is subjective in nature, recent market data gathered suggest that the composite rates used for mortgages and senior notes are consistent with current market trends.