Fair Value (Details 2) (USD $) In Thousands, unless otherwise specified			6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Maximum [Member] Credit-Oriented Investments [Member]	Jun. 30, 2012 Maximum [Member] Real estate-oriented investments [Member]	Jun. 30, 2012 Maximum [Member] Equity investments [Member]	Jun. 30, 2012 Minimum [Member] Credit-Oriented Investments [Member]	Jun. 30, 2012 Minimum [Member] Real estate-oriented investments [Member]	Jun. 30, 2012 Minimum [Member] Equity investments [Member]	Jun. 30, 2012 Level 3 [Member]	Dec. 31, 2011 Level 3 [Member]	Jun. 30, 2012 Level 3 [Member] Credit-Oriented Investments [Member] Discounted cash flow [Member]	Jun. 30, 2012 Level 3 [Member] Credit-Oriented Investments [Member] Market approach (comparable companies) [Member]	Jun. 30, 2012 Level 3 [Member] Credit-Oriented Investments [Member] Market approach (value of underlying assets) [Member]	Jun. 30, 2012 Level 3 [Member] Credit-Oriented Investments [Member] Recent transaction price [Member]	Jun. 30, 2012 Level 3 [Member] Credit-Oriented Investments [Member] Broker quotations [Member]	Jun. 30, 2012 Level 3 [Member] Other [Member]	Jun. 30, 2012 Level 3 [Member] Real estate-oriented investments [Member] Discounted cash flow [Member]	Jun. 30, 2012 Level 3 [Member] Real estate-oriented investments [Member] Market approach (comparable companies) [Member]	Jun. 30, 2012 Level 3 [Member] Real estate-oriented investments [Member] Market approach (value of underlying assets) [Member]	Jun. 30, 2012 Level 3 [Member] Real estate-oriented investments [Member] Recent transaction price [Member]	Jun. 30, 2012 Level 3 [Member] Equity investments [Member] Market approach (comparable companies) [Member]	Jun. 30, 2012 Level 3 [Member] Equity investments [Member] Market approach (value of underlying assets) [Member]	Jun. 30, 2012 Level 3 [Member] Equity investments [Member] Recent transaction price [Member]
Summary of valuation techniques and quantitative information
Investments, at fair value	$ 38,835,612	$ 38,614,226							$ 17,570,832	$ 15,673,386	$ 1,525,368	$ 1,280,623	$ 218,256	$ 1,230,611	$ 1,223,835	$ 19,965	$ 1,992,612	$ 368,714	$ 472,075	$ 726,147	$ 5,875,654	$ 1,442,814	$ 1,194,158
Discount rate			16.00%	38.00%		7.00%	8.00%
Earnings multiple			16	14	16	4	12	4
Underlying asset multiple			1.2	1.3	1.2	1	1.2	1
Terminal capitalization rate				0.11			0.06
Direct capitalization rate				0.09			0.07
Net operating income growth rate				27.00%			2.00%
Absorption rate				67.00%			13.00%