Disposed Properties (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013 Assets
Discontinued Operations and Disposal Groups [Abstract]
Gain (loss) on Sale of Properties	$ 6,533	$ 787	$ 19,118	$ 14,001
Properties Contributed to an Unconsolidated Entity				14
Gain on Contribution of Properties to Joint Venture				12,783
Proceeds from sale of investment properties, net			$ 774,634	$ 1,884,538