Preferred Equity and Mezzanine Loan Investments (Details) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2019 USD ($) loan	Dec. 31, 2018 USD ($) loan
Variable Interest Entity [Line Items]
Total	$ 175,128	$ 165,555
Georgia
Variable Interest Entity [Line Items]
Geographic concentration, percent	14.60%	15.30%
Texas
Variable Interest Entity [Line Items]
Geographic concentration, percent	11.90%	16.60%
Alabama
Variable Interest Entity [Line Items]
Geographic concentration, percent	11.10%	8.60%
Florida
Variable Interest Entity [Line Items]
Geographic concentration, percent	10.80%	11.30%
Tennessee
Variable Interest Entity [Line Items]
Geographic concentration, percent	10.20%	6.80%
South Carolina
Variable Interest Entity [Line Items]
Geographic concentration, percent	9.10%	9.50%
Virginia
Variable Interest Entity [Line Items]
Geographic concentration, percent	8.60%	9.10%
Preferred equity and mezzanine loan investments
Variable Interest Entity [Line Items]
Investment amount	$ 176,486	$ 166,789
Deferred loan fees, net	(1,358)	(1,234)
Total	$ 175,128	$ 165,555
Number of delinquent loans \| loan	0	0

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Net carrying amount of the assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), when the reporting entity is not the VIE's primary beneficiary.

+ References

No definition available.

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Carrying amount of the liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

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