Commitment and Contingencies (Tables)

12 Months Ended

Dec. 31, 2011

Commitments and Contingencies [Abstract]

Summary of the Company's real estate development commitments

					Expected Costs
	Number of		Costs Incurred		to Complete		Ownership
	Properties		to Date		(unaudited)		Stake
Wholly owned — under development		7	$	248,746	$	425,529		100	%
Joint ventures:
Consolidated Joint Ventures		1		13,072		32,928		90	%
Unconsolidated Joint Ventures		3		37,913		142,987		95	%
			$	299,731	$	601,444

Future minimum lease payments

	Ground		Office
	Leases (a)		Space
2012	$	5,043	$	458
2013		5,043		478
2014		5,043		498
2015		5,043		499
2016		5,043		40
Thereafter		314,914		—
	$	340,129	$	1,973

(a) For purposes of our ground lease contracts, the Company uses the minimum lease payment, if stated in the agreement. For ground lease agreements where there is a reset provision based on the communities appraised value or consumer price index but does not include a specified minimum lease payment, the Company uses the current rent over the remainder of the lease term.