Fair Value Measurements (Details 2) (Fair Value, Measurements, Nonrecurring, Level 3, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Impairment Disclosure
Impairment charges on properties	$ 735	$ 5,963
Continuing Operations
Impairment Disclosure
Impairment charges on properties	735	2,684
Continuing Operations | Equity investments in real estate
Impairment Disclosure
Total fair value measurements	0	14,220
Impairment charges on properties	735	2,684
Discontinued Operations
Impairment Disclosure
Impairment charges on properties	0	3,279
Discontinued Operations | Real Estate
Impairment Disclosure
Total fair value measurements	0	3,350
Impairment charges on properties	0	2,208
Discontinued Operations | Operating real estate
Impairment Disclosure
Total fair value measurements	0	3,812
Impairment charges on properties	$ 0	$ 1,071