Disposals and Discontinued Operations (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Portfolio sale 3 malls and 3 associated centers [Member] Properties	Mar. 31, 2014 Georgia Square and Georgia Square Plaza [Member]	Mar. 31, 2013 Georgia Square and Georgia Square Plaza [Member]	Mar. 31, 2013 1500 Sunday Drive [Member]	Mar. 31, 2013 Peninsula Business Center I and II [Member]	Mar. 31, 2013 Lake Point and SunTrust Office [Member]	Mar. 31, 2013 Various [Member]	Mar. 31, 2014 Citadel Mall [Member]	Jun. 30, 2013 Citadel Mall [Member]	Jan. 31, 2014 Citadel Mall [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Non-recourse debt										$ 68,563,000		$ 68,169,000
Loss on impairment	17,150,000	0									20,453,000
Gain on extinguishment of debt	42,660,000	0								43,909,000
Sales of real estate		220,425,000			176,000,000	8,300,000	5,250,000	30,875,000
Proceeds from sale of real estate		215,450,000			171,977,000	7,862,000	5,121,000	30,490,000
Gain (loss) from disposal of real estate		781,000		0		(634,000)	590,000	824,000	1,000
Impairment of disposed real estate			5,234,000
Properties sold			6
Revenues of discontinued operations		7,909,000
Net investment in real estate at time of sale	$ 42,693,000