Summary of Significant Accounting Policies - Narrative (Details)				3 Months Ended
	Apr. 01, 2019 USD ($)	Jun. 07, 2016	Jul. 08, 2014	Mar. 31, 2020 USD ($) numberOfLoanPools $ / shares shares	Mar. 31, 2019 USD ($)	Nov. 19, 2018 USD ($)	Aug. 18, 2017 USD ($)	Apr. 25, 2017 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of loan pools | numberOfLoanPools				4
Amortization of debt discount					$ 3,200,000
Convertible senior note repurchase				$ 81,000
Convertible Notes Payable				8,000,000.0
Payments for Repurchase of Convertible Notes				8,200,000
Provision for credit losses				$ (10,156,000)	$ 0
Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of an assets				27 years 6 months
Management Agreement | Thetis
Summary Of Significant Accounting Policies [Line Items]
Terms of agreement				15 years
Servicing Agreement | Gregory
Summary Of Significant Accounting Policies [Line Items]
Servicing fees percentage				0.42%
Percentage of Fair Market Value of REO			1.00%
Servicing Fees, Consecutive Payments | numberOfLoanPools				7
Percentage of Purchase Price of REO			1.00%
Servicing Agreement | Gregory | Minimum
Summary Of Significant Accounting Policies [Line Items]
Servicing fees percentage				0.65%
Servicing Agreement | Gregory | Maximum
Summary Of Significant Accounting Policies [Line Items]
Servicing fees percentage				1.25%
Amended And Restated Management Agreement [Member] | Thetis
Summary Of Significant Accounting Policies [Line Items]
Period of common shares held as base management fee (at least)				3 years
2014 Director Equity Plan
Summary Of Significant Accounting Policies [Line Items]
Number of shares available under for distribution (in shares) | shares				78,000
Vesting period				1 year
Annual Retainer Received In Shares	40.00%			50.00%
Annual Retainer Received In Cash	60.00%			50.00%
2014 Director Equity Plan | Restricted stock
Summary Of Significant Accounting Policies [Line Items]
Number of shares issued to independent directors (in shares) | shares				2,000
Annual retainer amount	$ 100,000			$ 75,000
2016 Equity Incentive Plan
Summary Of Significant Accounting Policies [Line Items]
Vesting period		3 years
Fraction of award vesting period		0.3333
Percentage of outstanding shares on a fully diluted basis (up to)		5.00%
Convertible Notes Payable
Summary Of Significant Accounting Policies [Line Items]
Aggregate principal								$ 87,500,000
Additional aggregate principal						$ 15,900,000	$ 20,500,000
Interest Rate				7.25%			7.25%	7.25%
Principal amount of note (in dollars per share) | $ / shares				$ 25.00
Amortization of debt discount				$ 300,000
Common Stock | Convertible Notes Payable
Summary Of Significant Accounting Policies [Line Items]
Conversion rate				1.7279
Conversion price (in dollars per share) | $ / shares				$ 14.47