Use of Special Purpose Entities and Variable Interest Entities - Classification and Carrying Value of Unconsolidated VIEs (Details) - USD ($) $ in Thousands		Mar. 31, 2016		Dec. 31, 2015
Variable Interest Entity [Line Items]
Investment securities available for sale, at fair value		$ 41,490	[1]	$ 40,734	[2]
Receivables and other assets		226,369		215,808
Total assets	[3]	9,252,944		9,056,242
Multi-Family CMBS
Variable Interest Entity [Line Items]
Investment securities available for sale, at fair value		41,490		40,734
Receivables and other assets		75		76
Total assets		41,565		40,810
Mezzanine loan, preferred equity and investments in unconsolidated entities
Variable Interest Entity [Line Items]
Receivables and other assets		128,027		129,887
Total assets		128,027		129,887
Total Unconsolidated VI Es
Variable Interest Entity [Line Items]
Investment securities available for sale, at fair value		41,490		40,734
Receivables and other assets		128,102		129,963
Total assets		$ 169,592		$ 170,697

[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 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).

[3] Our condensed 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 March 31, 2016 and December 31, 2015, assets of consolidated VIEs totaled $7,432,157 and $7,413,082, respectively, and the liabilities of consolidated VIEs totaled $7,175,369 and $7,077,175, respectively. See Note 7 for further discussion.