Other Investments (Schedule of Other Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity method investments, carrying value	$ 228,756		$ 228,756		$ 254,172
Earnings (loss) from equity method investments	39,447	$ 8,785	47,714	$ 15,332
Proceeds from sale of equity method investments			39,810	0
Other real estate equity investments
Schedule of Equity Method Investments [Line Items]
Equity method investments, carrying value	74,381		74,381		81,452
Earnings (loss) from equity method investments	28,600	(337)	26,898	(1,638)
Proceeds from sale of equity method investments			39,800
Equity method investment, realized gain on disposal			31,500
Net Lease Venture
Schedule of Equity Method Investments [Line Items]
Equity method investments, carrying value	67,895		67,895		69,096
Earnings (loss) from equity method investments	944	1,666	1,890	3,299
Other Investments
Schedule of Equity Method Investments [Line Items]
Equity method investments, carrying value	58,922		58,922		73,525
Earnings (loss) from equity method investments	4,723	2,357	5,525	4,053
Marina Palms
Schedule of Equity Method Investments [Line Items]
Equity method investments, carrying value	27,558		27,558		$ 30,099
Earnings (loss) from equity method investments	5,180	5,099	13,401	9,618
Noncontrolling Interests
Schedule of Equity Method Investments [Line Items]
EquityMethodInvestmentRealizedGainLossOnDisposalPortionAttributableToNonControllingInterest			10,100
Oak Hill Funds
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity method investments	$ 500	$ 700	$ 3,700	$ 2,200