Fair Value Measurements (Details 2) (Fair Value, Measurements, Nonrecurring, Level 3, USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Impairment Disclosure
Impairment charges on properties	$ 2,066	$ 4,123	$ 2,801	$ 10,086
Continuing Operations
Impairment Disclosure
Impairment charges on properties	2,066	2,844	2,801	5,528
Continuing Operations | Equity investments in real estate
Impairment Disclosure
Total fair value measurements	0	11,140	0	11,140
Impairment charges on properties	0	2,844	735	5,528
Continuing Operations | Real Estate
Impairment Disclosure
Total fair value measurements	5,200	0	5,200	0
Impairment charges on properties	2,066	0	2,066	0
Discontinued Operations
Impairment Disclosure
Impairment charges on properties	0	1,279	0	4,558
Discontinued Operations | Real Estate
Impairment Disclosure
Total fair value measurements	0	6,908	0	6,908
Impairment charges on properties	0	1,279	0	3,487
Discontinued Operations | Operating real estate
Impairment Disclosure
Total fair value measurements	0	0	0	3,709
Impairment charges on properties	$ 0	$ 0	$ 0	$ 1,071