Carrying value as of the balance sheet date, including the current and noncurrent portions, of commercial real estate debt fund (with maturities initially due after one year or beyond the operating cycle, if longer). The Debt fund is secured by a portfolio of loan obligations, which includes first mortgage bridge loans, senior participations interests in first mortgage bridge loans, subordinate participation interest in first mortgage bridge loans and participation interests in mezzanine loans. The Debt Fund allows, for a period of three years, principal proceeds from portfolio assets to be reinvested in qualifying replacement assets, subject to certain conditions.

No definition available.

Variable Interest Entities (Details)	9 Months Ended
Variable Interest Entities (Details)	Sep. 30, 2018 USD ($) item	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Variable Interest Entities
Loan loss reserves related to VIEs	$ 60,951,000	$ 58,733,000	$ 62,783,000	$ 83,256,000	$ 81,256,000	$ 83,712,000
Assets:
Restricted cash	202,736,000		139,398,000
Loans and investments, net	3,097,689,000		2,579,127,000
Due from related party	97,505,000		688,000
Other assets	79,301,000		62,264,000
Total assets	4,534,260,000		3,625,945,000
Liabilities:
Collateralized loan obligations	1,592,089,000		1,418,422,000
Debt fund	68,099,000		68,084,000
Other liabilities	100,970,000		99,813,000
Total liabilities	3,567,788,000		2,761,389,000
Consolidated VIEs
Assets:
Restricted cash	201,986,000		138,736,000
Loans and investments, net	1,885,104,000		1,836,744,000
Due from related party	95,045,000
Other assets	15,408,000		14,011,000
Total assets	2,197,543,000		1,989,491,000
Liabilities:
Collateralized loan obligations	1,592,089,000		1,418,422,000
Debt fund	68,099,000		68,084,000
Other liabilities	3,013,000		2,046,000
Total liabilities	$ 1,663,201,000		$ 1,488,552,000
Unconsolidated VIEs
Variable Interest Entities
Number of VIEs where the reporting entity is not VIE's primary beneficiary and VIEs have variable interest \| item	23
Carrying Amount	$ 341,198
Carrying amount of loans and investments before reserves related to VIEs	130,200,000
Loan loss reserves related to VIEs	59,300,000
Exposure to real estate debt	3,010,000,000
Unconsolidated VIEs \| Loans
Variable Interest Entities
Carrying Amount	287,166,000
Unconsolidated VIEs \| B Piece bonds
Variable Interest Entities
Carrying Amount	50,520,000
Unconsolidated VIEs \| Agency interest only strips
Variable Interest Entities
Carrying Amount	$ 3,512,000