Debt Obligations, net (Encumbered/Unencumbered Assets) (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Real estate, net		$ 2,538,816		$ 2,676,714
Real estate available and held for sale		288,021		285,982
Loans receivable and other lending investments, net	[1]	1,567,296		1,377,843
Other investments		289,500		354,119
Cash and other assets		989,730		768,475
Total assets		5,673,363		5,463,133
Reserves for loan losses		(121,934)	$ (102,783)	(98,490)	$ (137,904)	$ (370,076)	$ (377,204)
Loan Participations Payable, net		141,452		0
Encumbered Assets
Debt Instrument [Line Items]
Real estate, net		880,745		620,378
Real estate available and held for sale		10,496		10,496
Loans receivable and other lending investments, net	[2]	102,218		46,515
Other investments		18,509		17,708
Cash and other assets		0		0
Total assets		1,011,968		695,097
Unencumbered Assets [Member]
Debt Instrument [Line Items]
Real estate, net		1,658,071		2,056,336
Real estate available and held for sale		277,525		275,486
Loans receivable and other lending investments, net	[2]	1,349,876		1,364,828
Other investments		270,991		336,411
Cash and other assets		989,730		768,475
Total assets		4,546,193		4,801,536
Collectively Evaluated for Impairment [Member]
Debt Instrument [Line Items]
Reserves for loan losses	[3]	(27,100)		(33,500)
Loan Participations Payable [Member]
Debt Instrument [Line Items]
Loan Participations Payable, net		$ 142,300		$ 0

[1] The Company's recorded investment in loans as of June 30, 2015 and December 31, 2014 includes accrued interest of $8.8 million and $7.0 million, respectively, which are included in "Accrued interest and operating lease income receivable, net" on the Company's Consolidated Balance Sheets.

[2] As of June 30, 2015 and December 31, 2014, the amounts presented exclude general reserves for loan losses of $27.1 million and $33.5 million, respectively.

[3] The carrying value of these loans include unamortized discounts, premiums, deferred fees and costs aggregating to a net discount of $11.1 million and $10.6 million as of June 30, 2015 and December 31, 2014, respectively.