Supplemental Disclosure of Non-Cash Investing and Financing Activities (Details) (USD $) In Thousands	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Issuance of common stock as deferred compensation	$ 545	$ 402
Issuance of units in the operating partnership	20,222
Redemption of units in the operating partnership	725
Derivative instruments at fair value	1,071	15,296
Assignment of debt investment to joint venture	286,571
Mortgage assigned to joint venture	30,000
Tenant improvements and capital expenditures payable	8,389	7,363
Assumption of mortgage loans	663,767	139,672
Debt and other investments acquired		30,000
Fair value adjustment to noncontrolling interest in operating partnership	42,296	3,940
Accrued acquisition liabilities	44,500
Consolidation of real estate investments	557,314
Deconsolidation of real estate investments - assets		60,783
Deconsolidation of real estate investments - liabilities		$ 47,533

Future cash outflow to pay for liabilities incurred by the acquirer in a business acquisition.

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Represents the change in the carrying value of real estate investments resulting from consolidation.

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Represents the change in the carrying value of real estate investment assets resulting from deconsolidation.

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Represents fair value adjustments to derivative instruments.

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Represents the fair value adjustment to the noncontrolling interest in the operating partnership.

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Future cash outflow to pay for purchases of fixed assets that have occurred.

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The total fair value of shares issued during the period under a deferred compensation arrangement.

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The fair value of assets acquired in noncash investing or financing activities.

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The fair value of loans assumed in noncash investing or financing activities.

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- Definition

Total change in each class of partners' capital accounts during the year due to redemptions and adjustments to redemption value. All partners include general, limited and preferred partners.

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Total change in each class of partners' capital accounts during the year due to the sale of units. All partners include general, limited and preferred partners.

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The fair value of transfer of mortgage payable in noncash investing or financing activities.

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Value of investments transferred in noncash transactions.

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