Other Assets and Liabilities - Additional Information (Details) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($) partnership property	Dec. 31, 2018 USD ($) partnership property
Other Assets and Other Liabilities [Line Items]
Investment receivable	$ 6,494	$ 6,959	$ 6,959
Real estate owned (REO)	7,275	$ 3,943	$ 3,943
REO liquidations	2,000
Unrealized gain resulting from market valuation adjustments on REO	200
Number of partnerships consolidated \| partnership		2	2
Payable to minority partner	16,696	$ 14,331	$ 14,331
Net income (loss) allocated to Limited Partners (less than)	(200)
Contingent consideration	24,621	$ 0	$ 0
Legacy Sequoia
Other Assets and Other Liabilities [Line Items]
Real estate owned (REO)	2,000
Amount related to transfers into REO (less than)	$ 100
Number of REO properties recorded on balance sheet (in properties) \| property	9	13	13
Bridge Loan \| Debt Securities
Other Assets and Other Liabilities [Line Items]
Real estate owned (REO)	$ 5,000
Amount related to transfers into REO (less than)	$ 5,000
Number of REO properties recorded on balance sheet (in properties) \| property	1

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Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

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