Supplemental Disclosure to Statement of Cash Flows - Additional Information (Detail) $ in Thousands		1 Months Ended	3 Months Ended
	Mar. 16, 2018 USD ($)	Mar. 31, 2018 USD ($) Loan	Mar. 31, 2019 USD ($)		Mar. 31, 2018 USD ($) Loan	Dec. 31, 2018 USD ($)	[2]
Cash Flow Supplemental Disclosures [Line Items]
Unpaid principal balance		$ 90,260			$ 90,260
Number of loans held for sale | Loan		9			9
Principal balance			$ 6,967
Increase in non-cash investment in real estate			7,448
Decrease in non-cash invesment in mortgage loans			7,866
Plaz America
Cash Flow Supplemental Disclosures [Line Items]
Acquired the non-controlling interests	$ 343				$ 343
Commercial Portfolio Segment
Cash Flow Supplemental Disclosures [Line Items]
Unpaid principal balance			438,542	[1]		$ 502,974
Principal balance			$ 438,641	[1]		$ 503,071
Commercial Portfolio Segment | Commercial Mortgage Loans Sold
Cash Flow Supplemental Disclosures [Line Items]
Unpaid principal balance		$ 90,260			90,260
Commercial Portfolio Segment | Commercial Mortgage Loans Held for Sale
Cash Flow Supplemental Disclosures [Line Items]
Principal balance		$ 38,394			$ 38,394

[1] Includes $53,128 of cash flow loans, of which $7,148 are commercial mortgage loans, $21,114 are mezzanine loans and $24,866 are preferred equity interests. See Note 2: Summary of Significant Accounting Policies, (j) Revenue Recognition, for further discussion of our cash flow loans.

[2] Includes $54,621 of cash flow loans, of which $8,579 are commercial mortgage loans, $21,114 are mezzanine loans and $24,928 are preferred equity interests. See Note 2: Summary of Significant Accounting Policies, (j) Revenue Recognition, for further discussion of our cash flow loans.