Fair Value of Derivatives and Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value of Derivatives and Financial Instruments [Abstract]

Estimated fair values of financial instruments either recorded or disclosed on a recurring basis

			Fair Value at December 31, 2011 Using
			Quoted Prices in
			Active Markets
			for Identical		Significant Other		Significant
			Assets or		Observable		Unobservable
			Liabilities		Inputs		Inputs
	December 31, 2011		(Level 1)		(Level 2)		(Level 3)
Description:
Derivatives- Interest rate contracts (c)	$	89	$	—	$	89	$	—
Total assets	$	89	$	—	$	89	$	—
Derivatives- Interest rate contracts (c)	$	13,660	$	—	$	13,660	$	—
Contingent purchase Consideration (d)		3,000		—		—		3,000
Secured debt instruments- fixed rate: (a)
Mortgage notes payable		635,531		—		—		635,531
Fannie Mae credit facilities		799,584		—		—		799,584
Secured debt instruments- variable rate: (a)		—
Mortgage notes payable		151,685		—		—		151,685
Tax-exempt secured notes payable		94,700		—		—		94,700
Fannie Mae credit facilities		310,451		—		—		310,451
Unsecured debt instruments: (b)		—
Commercial bank		421,000		—		—		421,000
Senior Unsecured Notes		1,675,189		—		—		1,675,189
Total liabilities	$	4,104,800	$	—	$	13,660	$	4,091,140

			Fair Value at December 31, 2010 Using
			Quoted Prices in
			Active Markets
			for Identical		Significant Other		Significant
			Assets or		Observable		Unobservable
			Liabilities		Inputs		Inputs
	December 31, 2010		(Level 1)		(Level 2)		(Level 3)
Description:
Available-for-sale equity securities	$	3,866	$	3,866	$	—	$	—
Derivatives- Interest rate contracts (c)		514		—		514		—
Total assets	$	4,380	$	3,866	$	514	$	—
Derivatives- Interest rate contracts (c)	$	6,597	$	—	$	6,597	$	—
Contingent purchase consideration (d)		5,402		—		—		5,402
Secured debt instruments- fixed rate: (a)
Mortgage notes payable		306,515		—		—		306,515
Tax-exempt secured notes payable		13,885		—		—		13,885
Fannie Mae credit facilities		927,413		—		—		927,413
Secured debt instruments- variable rate: (a)
Mortgage notes payable		405,641		—		—		405,641
Tax-exempt secured notes payable		94,700		—		—		94,700
Fannie Mae credit facilities		260,450		—		—		260,450
Unsecured debt instruments: (b)
Commercial bank		31,750		—		—		31,750
Senior Unsecured Notes		1,625,492		264,849		—		1,360,643
Total liabilities	$	3,677,845	$	264,849	$	6,597	$	3,406,399
Redeemable Non-controlling Interests	$	119,057	$	—	$	119,057	$	—

(a)	See Note 6, Secured Debt
(b)	See Note 7, Unsecured Debt
(c)	See Note 13, Derivatives and Hedging Activity
(d)	In the first quarter of 2010, the Company accrued a liability of $6.0 million related to a contingent purchase consideration on one of its properties. The contingent consideration was determined based on the fair market value of the related asset which is estimated using Level 3 inputs utilized in a third party appraisal. The Company paid approximately $635,000 of the liability during the year ended December 31, 2010. The remaining balance of $5.4 million was paid during the year ended December 31, 2011 in conjunction with the sale of the property. The fair value of the contingent purchase consideration is also inclusive of $3.0 million accrued in relation to our acquisition of a development property in a consolidated joint venture as of and during the year ended December 31, 2011. (See Note 5, Joint Ventures.)