Debt Obligations, net (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended			6 Months Ended					1 Months Ended		3 Months Ended		6 Months Ended			6 Months Ended			1 Months Ended		6 Months Ended				1 Months Ended	6 Months Ended		1 Months Ended	6 Months Ended		12 Months Ended	1 Months Ended		3 Months Ended		6 Months Ended			1 Months Ended	6 Months Ended		1 Months Ended		1 Months Ended			3 Months Ended	6 Months Ended			6 Months Ended		6 Months Ended
	Apr. 30, 2012 LeaseAssets	Jun. 30, 2012		Jun. 30, 2011	Jun. 30, 2012		Jun. 30, 2011	Dec. 31, 2011		Mar. 31, 2012 2012 Secured Credit Facilities tranches	Mar. 31, 2012 Secured 2012 Tranche A-1 Facility Due 2016	Jun. 30, 2012 Secured 2012 Tranche A-1 Facility Due 2016		Jun. 30, 2012 Secured 2012 Tranche A-1 Facility Due 2016		Dec. 31, 2011 Secured 2012 Tranche A-1 Facility Due 2016	Jun. 30, 2012 Secured 2012 Tranche A-2 Facility Due 2017		Dec. 31, 2011 Secured 2012 Tranche A-2 Facility Due 2017	Jun. 30, 2012 Unsecured Notes LIBOR plus 0.50% senior convertible notes		Jun. 30, 2012 Unsecured Notes LIBOR plus 0.50% senior convertible notes		Dec. 31, 2011 Unsecured Notes LIBOR plus 0.50% senior convertible notes		Jun. 30, 2012 Unsecured Line of credit due June 2012	Jun. 30, 2012 Unsecured Line of credit due June 2012	Dec. 31, 2011 Unsecured Line of credit due June 2012	Mar. 31, 2011 Secured 2011 Tranche A-2 Facility Due 2014	Jun. 30, 2012 Secured 2011 Tranche A-2 Facility Due 2014		Dec. 31, 2011 Secured 2011 Tranche A-2 Facility Due 2014	Mar. 31, 2011 2011 Secured Credit Facilities tranches	Mar. 31, 2011 Secured 2011 Tranche A-1 Facility Due 2013	Jun. 30, 2012 Secured 2011 Tranche A-1 Facility Due 2013		Jun. 30, 2012 Secured 2011 Tranche A-1 Facility Due 2013		Dec. 31, 2011 Secured 2011 Tranche A-1 Facility Due 2013	Apr. 30, 2012 Secured Term Loan LIBOR plus 4.50% due 2014	Jun. 30, 2012 Secured Term Loan LIBOR plus 4.50% due 2014	Jun. 30, 2012 Unsecured Credit Facilities	Jan. 31, 2011 Secured Notes 10.0% senior notes due 2014	Jan. 02, 2011 Secured Notes 10.0% senior notes due 2014	May 31, 2012 Unsecured Notes 9.0% senior notes	Jun. 30, 2012 Unsecured Notes 9.0% senior notes	Dec. 31, 2011 Unsecured Notes 9.0% senior notes	Jun. 30, 2012 Senior unsecured notes with various maturities ranging from March 2012 to October 2014	Jun. 30, 2012 Senior unsecured notes with various maturities ranging from March 2012 to October 2014	Jun. 30, 2012 Unsecured Notes 5.50% senior notes	Dec. 31, 2011 Unsecured Notes 5.50% senior notes	Jun. 30, 2012 Unsecured Notes 5.15% senior notes	Dec. 31, 2011 Unsecured Notes 5.15% senior notes	Jun. 30, 2012 Secured Credit Facility	Dec. 31, 2011 Secured Credit Facility	Mar. 31, 2011 Minimum Secured 2012 Tranche A-1 Facility Due 2016	Jun. 30, 2012 Minimum Secured 2012 Tranche A-2 Facility Due 2017	Mar. 31, 2011 Minimum Secured 2011 Tranche A-2 Facility Due 2014	Mar. 31, 2011 Minimum Secured 2011 Tranche A-1 Facility Due 2013	Jun. 30, 2012 Real Estate Held for Investment (REHI)	Dec. 31, 2011 Real Estate Held for Investment (REHI)	Jun. 30, 2012 Other Real Estate Owned (OREO)	Dec. 31, 2011 Other Real Estate Owned (OREO)	Dec. 31, 2011 Maturing on or before June 2012 Secured 2011 Tranche A-1 Facility Due 2013	Jun. 30, 2012 Maturing on or before December 31, 2012 Secured 2012 Tranche A-1 Facility Due 2016	Dec. 31, 2011 Maturing on or before December 31, 2012 Secured 2011 Tranche A-1 Facility Due 2013	Jun. 30, 2012 Maturing on or before June 2013 Secured 2012 Tranche A-1 Facility Due 2016	Dec. 31, 2011 Maturing on or before June 2013 Secured 2011 Tranche A-1 Facility Due 2013
Debt Instrument [Line Items]
Variable interest rate, basis														LIBOR	[1]		LIBOR	[1]				LIBOR	[2]				LIBOR			LIBOR	[3]						LIBOR	[3]			LIBOR	LIBOR
Variable interest rate, spread (as a percent)												4.00%	[1]	4.00%	[1]		5.75%	[1]		0.50%	[2]	0.50%	[2]			0.85%	0.85%			5.75%	[3]				3.75%	[3]	3.75%	[3]			4.50%	0.85%														1.25%	1.25%	1.25%	1.25%
Number of tranches										2																							2
Borrowings on debt instrument										$ 880,000,000	$ 410,000,000						$ 470,000,000												$ 1,450,000,000				$ 2,950,000,000	$ 1,500,000,000
Percentage of par credit facilities were issued at												98.00%		98.00%			98.50%												98.50%					99.00%
Repayment of principal amount														81,400,000						315,600,000						244,000,000	243,700,000										853,900,000			50,800,000										90,300,000		169,700,000
Minimum aggregate cumulative amortization payment												41,000,000		41,000,000																					646,100,000		646,100,000		200,000,000																									450,000,000	41,000,000	750,000,000	600,000	1,500,000,000
Periods following the initial payment of amortization that additional amortization payments are due																																6 months
Maximum commencement period of amortization after repayment of the Tranche A-1 Facility					6 months
Amortization payment due on or before each six month anniversary after the repayment of the Tranche A-1 facility					150,000,000																											150,000,000
Gain (loss) on early extinguishment of debt, net		(4,868,000)		(1,047,000)	(3,164,000)		105,556,000					(3,100,000)		(3,100,000)																					(2,100,000)		(3,100,000)					(200,000)	109,000,000					300,000	3,200,000
Number of net lease assets sold (in lease assets)	12
Amount of debt extinguished																																											312,300,000						411,900,000
Stated interest rate (as a percent)																																												10.00%		9.00%				5.50%		5.15%
Carrying Value		5,661,964,000	[4]		5,661,964,000	[4]		5,874,183,000				328,605,000		328,605,000		0	470,000,000		0	469,166,000	[2]	469,166,000	[2]	784,750,000	[2]	0	0	243,650,000		1,450,000,000		1,450,000,000			646,068,000		646,068,000		961,580,000							275,000,000	0			0	92,845,000	0	263,466,000	3,133,098,000	2,704,772,000
Effective interest rate (as a percent)												5.25%		5.25%			7.00%			5.50%		5.50%								7.00%					5.00%		5.00%															5.15%
Percentage of issue price to principal amount																																													98.012%
Loans and other lending investments encumbered assets		1,723,459,000	[5]		1,723,459,000	[5]		1,780,591,000	[5]
Loans and other lending investments unencumbered assets		634,151,000	[5]		634,151,000	[5]		1,153,671,000	[5]
Encumbered property subject to or available for operating lease, net		1,272,528,000			1,272,528,000			1,173,982,000
Unencumbered property subject to or available for operating lease net		277,585,000			277,585,000			528,782,000
Rehi and oreo assets pledged as collateral																																																												425,514,000	359,597,000	417,011,000	177,092,000
Rehi and oreo assets not pledged as collateral																																																												824,167,000	868,537,000	305,156,000	500,366,000
Other encumbered investments		69,740,000			69,740,000			37,957,000
Other unencumbered investments		357,761,000			357,761,000			419,878,000
Cash and other assets pledged as collateral		0			0			0
Cash and other assets not pledged as collateral		935,940,000			935,940,000			590,884,000
Total encumbered assets		3,908,252,000			3,908,252,000			3,529,219,000
Total unencumbered assets		3,334,760,000			3,334,760,000			4,062,118,000
Reserve for loan losses		$ 56,800,000	[6]		$ 56,800,000	[6]		$ 73,500,000	[6]
Minimum ratio of unencumbered assets to unsecured indebtedness																																										1.2
Multiple of the minimum collateral coverage on outstanding borrowings																																																						1.25
Percentage of REIT taxable income permitted for distribution under debt covenants																																																						100.00%

[1] These loans each have a LIBOR floor of 1.25%. As of June 30, 2012, inclusive of the floors, the 2012 Tranche A-1 Facility and 2012 Tranche A-2 Facility loans incurred interest at a rate of 5.25% and 7.00% respectively.

[2] The Company's convertible senior floating rate notes due October 2012 ("Convertible Notes") are convertible at the option of the holders into 22.2 shares per $1,000 principal amount of Convertible Notes (reflecting a conversion price of $45.05), on or after August 15, 2012, or prior to that date if certain conditions are met. None of the conversion conditions have been met as of June 30, 2012. As of June 30, 2012, the unamortized discount on these notes was $2.5 million, the net carrying amount of the liability was $466.7 million and the carrying value of the additional paid-in-capital, or equity component of the convertible notes was $34.7 million. For the three and six months ended June 30, 2012, the Company recognized interest expense on the convertible notes of $3.1 million and $8.3 million, respectively, of which $1.8 million and $4.8 million, respectively, related to the amortization of the debt discount. For the three and six months ended June 30, 2011, the Company recognized interest expense on the convertible notes of $4.5 million and $8.9 million respectively, of which $2.9 million and $5.7 million, respectively, related to the amortization of the debt discount.

[3] These loans each have a LIBOR floor of 1.25%. As of June 30, 2012, inclusive of the floors, the 2011 Tranche A-1 Facility and 2011 Tranche A-2 Facility loans incurred interest at a rate of 5.00% and 7.00%, respectively.

[4] All of the Company's non-accrual loans are considered impaired and included in the table above. In addition, as of June 30, 2012 and December 31, 2011, certain loans modified through troubled debt restructurings with a recorded investment of $205.5 million and $255.3 million, respectively, are also included as impaired loans in accordance with GAAP although they are performing and on accrual status.

[5] As of June 30, 2012 and December 31, 2011, the amounts presented exclude general reserves for loan losses of $56.8 million and $73.5 million, respectively.

[6] The carrying value of these loans include unamortized discounts, premiums, deferred fees and costs aggregating to a net discount of $2.1 million and $0.2 million as of June 30, 2012 and December 31, 2011, respectively.