Use of Special Purpose Entities (SPE) and Variable Interest Entities (VIE) - Classification and Carrying Value of Unconsolidated VIEs (Details) - USD ($) $ in Thousands		Dec. 31, 2015		Dec. 31, 2014
Variable Interest Entity [Line Items]
Investment securities available for sale, at fair value, held in securitization trusts		$ 40,734	[1]	$ 38,594	[2]
Receivables and other Assets		219,130		222,491
Total	[3]	9,059,564		10,540,005
Multi-Family CMBS
Variable Interest Entity [Line Items]
Investment securities available for sale, at fair value, held in securitization trusts		40,734		38,594
Receivables and other Assets		76		80
Total		40,810		38,674
Mezzanine loan, preferred equity and investments in unconsolidated entities
Variable Interest Entity [Line Items]
Receivables and other Assets		129,887		72,799
Total		129,887		72,799
Total Unconsolidated VIEs
Variable Interest Entity [Line Items]
Investment securities available for sale, at fair value, held in securitization trusts		40,734		38,594
Receivables and other Assets		129,963		72,879
Total		$ 170,697		$ 111,473

[1] The Company classified the multi-family CMBS issued by two K-Series securitizations and held by this Financing VIE as available for sale securities as the purpose is not to trade these securities. The Financing VIE consolidated one K-Series securitization that issued certain of the multi-family CMBS owned by the Company, including its assets, liabilities, income and expenses, in its financial statements, as based on a number of factors, the Company determined that it was the primary beneficiary and has a controlling financial interest in this particular K-Series securitization (see Note 6).

[2] The Company classified the multi-family CMBS issued by two K-Series securitizations and held by the Financing VIE as available for sale securities as the purpose is not to trade these securities. The Financing VIE consolidated one K-Series securitization that issued certain of the multi-family CMBS owned by the Company, including its assets, liabilities, income and expenses, in its financial statements, as based on a number of factors, the Company determined that it was the primary beneficiary and has a controlling financial interest in this particular K-Series securitization (see Note 6).

[3] Our consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs") as the Company is the primary beneficiary of these VIEs. As of December 31, 2015 and December 31, 2014, assets of consolidated VIEs totaled $7,413,082 and $8,847,078, respectively, and the liabilities of consolidated VIEs totaled $7,078,162 and $8,457,034, respectively. See Note 7 for further discussion.