Real Estate Real Estate Dispositions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Disposed Properties			20
Disposed Units			5,337
Proceeds From Sale Of Property			$ 616,904
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	103,394	76,864	307,447	759,100
Consolidated Rental Properties [Member]
Disposed Properties			20
Disposed Units			5,337
Proceeds From Sale Of Property			$ 616,904