Debt and Preferred Equity Investments (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013		Dec. 31, 2012
Debt investment
Increase in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	$ 189,400,000		$ 205,200,000
Decrease in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	500,000		121,900,000
Aggregate weighted average current yield (as a percent)	10.69%
Debt and preferred equity investments	1,493,725,000			1,304,839,000
Loan loss reserve	0			(1,000,000)		(7,000,000)
Debt investment
Debt investment
Senior Financing	5,934,314,000
Debt and preferred equity investments	1,080,054,000	[1]		936,475,000	[1]
Loan loss reserve	0	[1]		(1,000,000)	[1]
Total, net of reserve	1,080,054,000	[1]		935,475,000	[1]
Funding obligation	55,165,000
Total fixed rate
Debt investment
Senior Financing	2,980,280,000
Carrying Value, Net of Discounts	408,986,000	[1]		385,604,000	[1]
Funding obligation	19,938,000
Total fixed rate | Junior Participation, March 2015
Debt investment
Senior Financing	398,500,000
Carrying Value, Net of Discounts	11,874,000	[1]		11,856,000	[1]
Funding obligation	0
Total fixed rate | Mezzanine Loan, February 2016
Debt investment
Senior Financing	205,000,000
Carrying Value, Net of Discounts	68,892,000	[1]		68,319,000	[1]
Funding obligation	0
Total fixed rate | Mezzanine Loan, March 2016
Debt investment
Senior Financing	0
Carrying Value, Net of Discounts	10,000,000	[1]		0	[1]
Funding obligation	0
Total fixed rate | Mortgage/Mezzanine Loan, May 2016
Debt investment
Senior Financing	166,030,000
Carrying Value, Net of Discounts	44,930,000	[1]		44,742,000	[1]
Funding obligation	0
Total fixed rate | Mezzanine Loan, May 2016
Debt investment
Senior Financing	177,000,000
Carrying Value, Net of Discounts	14,739,000	[1]		15,012,000	[1]
Funding obligation	0
Total fixed rate | Junior Participation, June 2016
Debt investment
Senior Financing	133,000,000
Carrying Value, Net of Discounts	49,000,000	[1]		49,000,000	[1]
Funding obligation	0
Total fixed rate | Mezzanine Loan, November 2016
Debt investment
Senior Financing	165,000,000
Carrying Value, Net of Discounts	71,370,000	[1]		71,312,000	[1]
Funding obligation	0
Total fixed rate | Mortgage/Mezzanine Loan, March 2017
Debt investment
Increase in accrued interest receivable	10,100,000
Senior Financing	1,109,000,000	[2]
Carrying Value, Net of Discounts	92,994,000	[1],[2]		80,983,000	[1],[2]
Funding obligation	0	[2]
Total fixed rate | Mezzanine Loan, June 2017
Debt investment
Senior Financing	521,750,000	[3]
Carrying Value, Net of Discounts	21,035,000	[1],[3]		20,954,000	[1],[3]
Funding obligation	19,938,000	[3]
Loan participation amount included in other assets and other liabilities	41,300,000
Total fixed rate | Mortgage Loan, August 2019
Debt investment
Senior Financing	0
Carrying Value, Net of Discounts	725,000	[1]		0	[1]
Funding obligation	0
Total fixed rate | Mezzanine Loan, September 2021
Debt investment
Senior Financing	15,000,000
Carrying Value, Net of Discounts	3,500,000	[1]		3,500,000	[1]
Funding obligation	0
Total fixed rate | Mezzanine Loan, November 2023
Debt investment
Senior Financing	90,000,000	[4]
Carrying Value, Net of Discounts	19,927,000	[1],[4]		19,926,000	[1],[4]
Funding obligation	0	[4]
Loan participation amount included in other assets and other liabilities	5,000,000
Total floating rate
Debt investment
Senior Financing	2,954,034,000
Debt and preferred equity investments	671,068,000	[1]		550,871,000	[1]
Funding obligation	35,227,000
Total floating rate | Mezzanine Loan, March 2016
Debt investment
Senior Financing	200,000,000
Debt and preferred equity investments	49,419,000	[1]		0	[1]
Funding obligation	0
Total floating rate | Mezzanine Loan, November 2016
Debt investment
Senior Financing	167,524,000
Debt and preferred equity investments	26,436,000	[1]		25,725,000	[1]
Funding obligation	10,743,000
Total floating rate | Junior Participation, June 2014
Debt investment
Senior Financing	57,750,000
Debt and preferred equity investments	10,875,000	[1]		10,873,000	[1]
Funding obligation	0
Total floating rate | Mortgage/Mezzanine Loan, July 2014
Debt investment
Senior Financing	330,000,000
Debt and preferred equity investments	131,853,000	[1]		131,724,000	[1]
Funding obligation	0
Total floating rate | Mezzanine Loan, August 2014
Debt investment
Senior Financing	180,000,000
Debt and preferred equity investments	59,932,000	[1]		59,892,000	[1]
Funding obligation	0
Total floating rate | Mezzanine Loan, September 2014
Debt investment
Senior Financing	481,309,000	[5]
Debt and preferred equity investments	19,675,000	[1],[5]		0	[1],[5]
Funding obligation	0	[5]
Total floating rate | Mezzanine Loan, October 2014
Debt investment
Senior Financing	90,718,000
Debt and preferred equity investments	38,948,000	[1]		38,549,000	[1]
Funding obligation	10,897,000
Total floating rate | Mortgage Loan, December 2014
Debt investment
Senior Financing	0	[6]
Debt and preferred equity investments	30,000,000	[1],[6]		30,000,000	[1],[6]
Funding obligation	0	[6]
Total floating rate | Junior Participation, February 2015
Debt investment
Senior Financing	84,000,000	[7]
Debt and preferred equity investments	24,943,000	[1],[7]		24,046,000	[1],[7]
Funding obligation	0	[7]
Total floating rate | Mezzanine Loan, September 2015
Debt investment
Senior Financing	110,000,000
Debt and preferred equity investments	49,230,000	[1]		49,110,000	[1]
Funding obligation	0
Total floating rate | Mezzanine Loan, December 2015
Debt investment
Senior Financing	93,850,000
Debt and preferred equity investments	36,565,000	[1]		27,662,000	[1]
Funding obligation	13,254,000
Total floating rate | Second Mezzanine Loan, March 2016
Debt investment
Senior Financing	775,000,000
Debt and preferred equity investments	73,067,000	[1]		72,823,000	[1]
Funding obligation	0
Total floating rate | Mezzanine Loan, June 2016
Debt investment
Senior Financing	160,000,000	[8]
Debt and preferred equity investments	22,538,000	[1],[8]		22,526,000	[1],[8]
Funding obligation	0	[8]
Loan participation amount included in other assets and other liabilities	7,400,000
Total floating rate | Mezzanine Loan, July 2016
Debt investment
Senior Financing	87,300,000
Debt and preferred equity investments	25,600,000	[1]		25,590,000	[1]
Funding obligation	0
Total floating rate | Mezzanine Loan, December 2016
Debt investment
Senior Financing	33,833,000
Debt and preferred equity investments	11,807,000	[1]		11,798,000	[1]
Funding obligation	333,000
Total floating rate | Mortgage/Mezzanine Loan, July 2018
Debt investment
Senior Financing	55,000,000
Debt and preferred equity investments	20,548,000	[1]		20,553,000	[1]
Funding obligation	0
Total floating rate | Mortgage/Mezzanine Loan, February 2019
Debt investment
Senior Financing	9,750,000
Debt and preferred equity investments	17,851,000	[1]		0	[1]
Funding obligation	0
Total floating rate | Mezzanine Loan, March 2019
Debt investment
Senior Financing	38,000,000
Debt and preferred equity investments	21,781,000	[1]		0	[1]
Funding obligation	$ 0

[1] Carrying value is net of discounts and deferred origination fees.

[2] During the three months ended March 31, 2014, we recognized $10.1 million of previously unaccrued interest income as deemed collectible as we expect the underlying property to be sold.

[3] 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

[4] 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

[5] 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.

[6] This loan was repaid in May 2014.

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

[8] 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.