Debt and Preferred Equity Investments (Details) (USD $)	6 Months Ended																																																												3 Months Ended	6 Months Ended																	1 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014 Debt investment		Dec. 31, 2013 Debt investment		Jun. 30, 2014 Total fixed rate		Dec. 31, 2013 Total fixed rate		Jun. 30, 2014 Total fixed rate Jr. Mortgage Participation, March 2015		Dec. 31, 2013 Total fixed rate Jr. Mortgage Participation, March 2015		Jun. 30, 2014 Total fixed rate Jr. Mortgage Participation/Mezzanine Loan, February 2016		Dec. 31, 2013 Total fixed rate Jr. Mortgage Participation/Mezzanine Loan, February 2016		Jun. 30, 2014 Total fixed rate Jr. Mortgage Participation/Mezzanine Loan, May 2016		Dec. 31, 2013 Total fixed rate Jr. Mortgage Participation/Mezzanine Loan, May 2016		Jun. 30, 2014 Total fixed rate Mezzanine Loan, May 2016		Dec. 31, 2013 Total fixed rate Mezzanine Loan, May 2016		Jun. 30, 2014 Total fixed rate Jr. Mortgage Participation, June 2016		Dec. 31, 2013 Total fixed rate Jr. Mortgage Participation, June 2016		Jun. 30, 2014 Total fixed rate Mezzanine Loan, November 2016		Dec. 31, 2013 Total fixed rate Mezzanine Loan, November 2016		Jun. 30, 2014 Total fixed rate Jr. Mortgage Participation/Mezzanine Loan, March 2017		Dec. 31, 2013 Total fixed rate Jr. Mortgage Participation/Mezzanine Loan, March 2017		Jun. 30, 2014 Total fixed rate Other, March 2017		Dec. 31, 2013 Total fixed rate Other, March 2017		Jun. 30, 2014 Total fixed rate Mezzanine Loan, June 2017		Dec. 31, 2013 Total fixed rate Mezzanine Loan, June 2017		Jun. 30, 2014 Total fixed rate Mortgage Loan, August 2019		Dec. 31, 2013 Total fixed rate Mortgage Loan, August 2019		Jun. 30, 2014 Total fixed rate Mezzanine Loan, September 2021		Dec. 31, 2013 Total fixed rate Mezzanine Loan, September 2021		Jun. 30, 2014 Total fixed rate Mezzanine Loan, November 2023		Dec. 31, 2013 Total fixed rate Mezzanine Loan, November 2023		Mar. 31, 2014 Total fixed rate Jr. Mortgage Participation, June 2014	Jun. 30, 2014 Total fixed rate Jr. Mortgage Participation, June 2014	Jun. 30, 2014 Total floating rate		Dec. 31, 2013 Total floating rate		Jun. 30, 2014 Total floating rate Mezzanine Loan, November 2016		Dec. 31, 2013 Total floating rate Mezzanine Loan, November 2016		Jun. 30, 2014 Total floating rate Jr. Mortgage Participation/Mezzanine Loan, July 2014		Dec. 31, 2013 Total floating rate Jr. Mortgage Participation/Mezzanine Loan, July 2014		Jun. 30, 2014 Total floating rate Mezzanine Loan, August 2014		Dec. 31, 2013 Total floating rate Mezzanine Loan, August 2014		Jun. 30, 2014 Total floating rate Jr. Mortgage Participation, August 2014		Dec. 31, 2013 Total floating rate Jr. Mortgage Participation, August 2014		Jun. 30, 2014 Total floating rate Mezzanine Loan, September 2014		Dec. 31, 2013 Total floating rate Mezzanine Loan, September 2014		Jun. 30, 2014 Total floating rate Mezzanine Loan, October 2014		Dec. 31, 2013 Total floating rate Mezzanine Loan, October 2014		Jun. 30, 2014 Total floating rate Jr. Mortgage Participation, February 2015		Dec. 31, 2013 Total floating rate Jr. Mortgage Participation, February 2015		Jun. 30, 2014 Total floating rate Mezzanine Loan April 2015		Dec. 31, 2013 Total floating rate Mezzanine Loan April 2015		Jun. 30, 2014 Total floating rate Mortgage/Mezzanine Loan June 2015		Dec. 31, 2013 Total floating rate Mortgage/Mezzanine Loan June 2015		Jun. 30, 2014 Total floating rate Mezzanine Loan, September 2015		Dec. 31, 2013 Total floating rate Mezzanine Loan, September 2015		Jun. 30, 2014 Total floating rate Mezzanine Loan, December 2015		Dec. 31, 2013 Total floating rate Mezzanine Loan, December 2015		Jun. 30, 2014 Total floating rate Mezzanine Loan, March 2016		Dec. 31, 2013 Total floating rate Mezzanine Loan, March 2016		Jun. 30, 2014 Total floating rate Mezzanine Loan, June 2016		Dec. 31, 2013 Total floating rate Mezzanine Loan, June 2016		Jun. 30, 2014 Total floating rate Mezzanine Loan, July 2016		Dec. 31, 2013 Total floating rate Mezzanine Loan, July 2016		Jun. 30, 2014 Total floating rate Mezzanine Loan, December 2016		Dec. 31, 2013 Total floating rate Mezzanine Loan, December 2016		Jun. 30, 2014 Total floating rate Jr. Mortgage Participation/Mezzanine Loan, July 2018		Dec. 31, 2013 Total floating rate Jr. Mortgage Participation/Mezzanine Loan, July 2018		Jun. 30, 2014 Total floating rate Mortgage/Mezzanine Loan, February 2019		Dec. 31, 2013 Total floating rate Mortgage/Mezzanine Loan, February 2019		Jun. 30, 2014 Total floating rate Mezzanine Loan, March 2019		Dec. 31, 2013 Total floating rate Mezzanine Loan, March 2019		Jun. 30, 2014 Total floating rate Mortgage Loan		Dec. 31, 2013 Total floating rate Mortgage Loan
Debt investment
Increase in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	$ 303,400,000	$ 298,800,000
Decrease in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	60,400,000	419,800,000
Aggregate weighted average current yield (as a percent)	10.69%
Funding Obligations					72,468,000				19,725,000				0				0				0				0				0				0				0	[1]			0	[1]			19,725,000	[2]			0				0				0	[3]					52,743,000				10,584,000				0	[4]			0	[5]			0	[6]			0	[7]			9,794,000				0	[8]			22,817,000				0				0				9,215,000				0				0	[9]			0				333,000				0				0				0				0	[10]
Senior Financing					5,818,222,000				2,979,409,000				398,500,000				205,000,000				165,159,000				177,000,000				133,000,000				165,000,000				1,109,000,000	[1]			0	[1]			521,750,000	[2]			0				15,000,000				90,000,000	[3]					2,838,813,000				168,485,000				330,000,000	[4]			180,000,000	[5]			57,750,000	[6]			481,309,000	[7]			93,279,000				84,000,000	[8]			50,000,000				0				110,000,000				107,157,000				775,000,000				160,000,000	[9]			115,000,000				33,833,000				55,000,000				0				38,000,000				0	[10]
Carrying Value, Net of Discounts									467,757,000	[11]	385,604,000	[11]	11,893,000	[11]	11,856,000	[11]	69,480,000	[11]	68,319,000	[11]	45,137,000	[11]	44,742,000	[11]	14,519,000	[11]	15,012,000	[11]	49,000,000	[11]	49,000,000	[11]	71,430,000	[11]	71,312,000	[11]	95,329,000	[1],[11]	26,884,000	[1],[11]	65,578,000	[1],[11]	54,099,000	[1],[11]	21,267,000	[11],[2]	20,954,000	[11],[2]	696,000	[11]	0	[11]	3,500,000	[11]	3,500,000	[11]	19,928,000	[11],[3]	19,926,000	[11],[3]
Debt and preferred equity investments	1,547,808,000		1,304,839,000		1,195,672,000	[11]	936,475,000	[11]																																																						30,000,000	727,915,000	[11]	550,871,000	[11]	26,655,000	[11]	25,725,000	[11]	131,987,000	[11],[4]	131,724,000	[11],[4]	59,974,000	[11],[5]	59,892,000	[11],[5]	10,875,000	[11],[6]	10,873,000	[11],[6]	19,487,000	[11],[7]	0	[11],[7]	40,125,000	[11]	38,549,000	[11]	24,959,000	[11],[8]	24,046,000	[11],[8]	22,002,000	[11]	0	[11]	108,981,000	[11]	0	[11]	49,354,000	[11]	49,110,000	[11]	40,662,000	[11]	27,662,000	[11]	73,326,000	[11]	72,823,000	[11]	22,549,000	[11],[9]	22,526,000	[11],[9]	24,907,000	[11]	25,590,000	[11]	11,816,000	[11]	11,798,000	[11]	20,544,000	[11]	20,553,000	[11]	17,923,000	[11]	0	[11]	21,789,000	[11]	0	[11]	0	[10],[11]	30,000,000	[10],[11]
Payments to Acquire Investments	256,730,000	277,877,000																																																												67,300,000
Loan loss reserve	0		(1,000,000)	(7,000,000)	0	[11]	(1,000,000)	[11]
Total, net of reserve					1,195,672,000	[11]	935,475,000	[11]
Accretion of unaccrued interest																																																													10,100,000
Face amount of mortgages																																																														66,700,000
Loan participation amount included in other assets and other liabilities																																													41,300,000												5,000,000																																																										7,400,000
Repayments or redemption of debt and preferred equity investments	$ 60,412,000	$ 432,667,000																																																																													$ 10,800,000

[1] During the three months ended March 31, 2014, we recognized $10.1 million of previously unaccrued interest income as deemed collectible as a result of the subsequent sale of the property, which closed in June 2014. In connection with the sale of the underlying property, our existing $66.7 million mezzanine loan was defeased and is now shown separately, as it is collateralized by defeasance securities. The buyer assumed our $30.0 million participating interest on the mortgage and we acquired a $67.3 million participating interest on the mezzanine loan.

[2] Carrying value is net of $41.3 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

[3] Carrying value is net of $5.0 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

[4] This loan was repaid in July 2014.

[5] This loan was repaid in August 2014.

[6] In June 2014, the loan maturity date was extended to August 2014 and $10.8 million has been repaid.

[7] This loan was previously included in other assets on the consolidated balance sheets. Following the sale of our interest in the partnership that is the borrower, the loan was reclassified to debt and preferred equity investments.

[8] In March 2014, the loan was extended to February 2015.

[9] Carrying value is net of $7.4 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

[10] This loan was repaid in May 2014.

[11] Carrying value is net of discounts, original issue discounts and deferred origination fees.