Fair Value of Financial Instruments	9 Months Ended
Sep. 30, 2012
Financial Instruments, Owned, at Fair Value [Abstract]
Fair Value of Financial Instruments	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 (classified within levels 1, 2 and 3 of the valuation hierarchy) – The carrying amounts reported in the balance sheets for these financial instruments approximate fair value because of their short maturities. Mezzanine Loans Receivable (classified within Level 2 of the valuation hierarchy) – The fair value estimated at September 30, 2012 and December 31, 2011 was $63.8 million and $45.0 million, respectively. The fair value is estimated by using a discounted cash flow analysis based on the current interest rates at which similar loans would be made. The carrying amount of these mezzanine loans receivable, including accrued interest, was approximately $64.7 million and $45.3 million at September 30, 2012 and December 31, 2011, respectively. Mortgage Notes Payable (classified within Level 2 of the valuation hierarchy) – The fair value estimated at September 30, 2012 and December 31, 2011 was $494.2 million and $545.6 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, including notes associated with properties held for sale, was approximately $454.9 million and $509.6 million at September 30, 2012 and December 31, 2011, respectively. Unsecured Senior Notes Payable (classified within Level 2 of the valuation hierarchy) – The fair value estimated at September 30, 2012 and December 31, 2011 was $748.6 million and $725.9 million, respectively, 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 $679.3 million and $688.8 million at September 30, 2012 and December 31, 2011, respectively. Term Loan (classified within Level 2 of the valuation hierarchy) – The fair value estimated at September 30, 2012 was $248.1 million, calculated based on the net present value of payments over the term of the loan using estimated market rates for similar notes and remaining terms. The carrying amount of this loan was approximately $250.0 million at September 30, 2012. The fair market value calculation of our debt as of September 30, 2012 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. Interest Rate Swap Agreements (classified within Level 2 of the valuation hierarchy) – The fair value of our interest rate swaps at September 30, 2012 was a liability of $7.7 million. See Note 18 above for a discussion of the method used to value the interest rate swaps. Redeemable Noncontrolling Interests (classified within Level 3 of the valuation hierarchy) – The carrying amount of the redeemable noncontrolling interests of $22.6 million and $22.8 million at September 30, 2012 and December 31, 2011, respectively, approximates their fair value. The valuation method used to estimate fair value of redeemable noncontrolling interests is based on discounted cash flow analyses. Investments In and Advances to Unconsolidated Joint Ventures (classified within Level 3 of the valuation hierarchy) – The carrying amount of the investments in and advances to unconsolidated joint ventures of $61.4 million and $50.2 million at September 30, 2012 and December 31, 2011, respectively, approximates its fair value as determined by discounted cash flow analyses.

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 (classified within levels 1, 2 and 3 of the valuation hierarchy) – The carrying amounts reported in the balance sheets for these financial instruments approximate fair value because of their short maturities.

Mezzanine Loans Receivable (classified within Level 2 of the valuation hierarchy) – The fair value estimated at September 30, 2012 and December 31, 2011 was $63.8 million and $45.0 million, respectively. The fair value is estimated by using a discounted cash flow analysis based on the current interest rates at which similar loans would be made. The carrying amount of these mezzanine loans receivable, including accrued interest, was approximately $64.7 million and $45.3 million at September 30, 2012 and December 31, 2011, respectively.

Mortgage Notes Payable (classified within Level 2 of the valuation hierarchy) – The fair value estimated at September 30, 2012 and December 31, 2011 was $494.2 million and $545.6 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, including notes associated with properties held for sale, was approximately $454.9 million and $509.6 million at September 30, 2012 and December 31, 2011, respectively.

Unsecured Senior Notes Payable (classified within Level 2 of the valuation hierarchy) – The fair value estimated at September 30, 2012 and December 31, 2011 was $748.6 million and $725.9 million, respectively, 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 $679.3 million and $688.8 million at September 30, 2012 and December 31, 2011, respectively.

Term Loan (classified within Level 2 of the valuation hierarchy) – The fair value estimated at September 30, 2012 was $248.1 million, calculated based on the net present value of payments over the term of the loan using estimated market rates for similar notes and remaining terms. The carrying amount of this loan was approximately $250.0 million at September 30, 2012.

The fair market value calculation of our debt as of September 30, 2012 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.

Interest Rate Swap Agreements (classified within Level 2 of the valuation hierarchy) – The fair value of our interest rate swaps at September 30, 2012 was a liability of $7.7 million. See Note 18 above for a discussion of the method used to value the interest rate swaps.

Redeemable Noncontrolling Interests (classified within Level 3 of the valuation hierarchy) – The carrying amount of the redeemable noncontrolling interests of $22.6 million and $22.8 million at September 30, 2012 and December 31, 2011, respectively, approximates their fair value. The valuation method used to estimate fair value of redeemable noncontrolling interests is based on discounted cash flow analyses.

Investments In and Advances to Unconsolidated Joint Ventures (classified within Level 3 of the valuation hierarchy) – The carrying amount of the investments in and advances to unconsolidated joint ventures of $61.4 million and $50.2 million at September 30, 2012 and December 31, 2011, respectively, approximates its fair value as determined by discounted cash flow analyses.