Debt - Narrative (Details)		1 Months Ended	3 Months Ended					6 Months Ended		12 Months Ended
		Aug. 31, 2022 USD ($)	Jun. 30, 2023 USD ($) securitization $ / shares	Mar. 31, 2023 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2020	Jun. 30, 2023 USD ($) securitization day counterparty facility trust $ / shares	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 14, 2022 USD ($)	Jan. 01, 2022 USD ($)	Dec. 09, 2021 USD ($)	Mar. 31, 2021
Debt Instrument [Line Items]
Percentage of guarantors beneficial interest (in percentage)			100.00%					100.00%
Cash collateral			$ 5,743,000					$ 5,743,000		$ 5,152,000
Number of securitizations completed | securitization								18
Number of securitizations outstanding | securitization			5					5
Convertible senior notes, net	[1]		$ 103,516,000					$ 103,516,000		104,256,000
Interest expense			15,039,000		$ 9,175,000			29,964,000	$ 17,781,000
Repurchase of the company's senior convertible notes								952,000	75,000
Reclass of conversion premium - convertible notes			314,711,000					$ 314,711,000		$ 335,328,000
Series A Preferred Stock
Debt Instrument [Line Items]
Preferred stock, fixed-to-floating rate cumulative redeemable							7.25%	7.25%		7.25%
Series B Preferred Stock
Debt Instrument [Line Items]
Preferred stock, fixed-to-floating rate cumulative redeemable				5.00%			5.00%	5.00%		5.00%
Accounting Standards Update 2020-06
Debt Instrument [Line Items]
Convertible senior notes, net												$ 700,000
Additional Paid-in Capital | Accounting Standards Update 2020-06
Debt Instrument [Line Items]
Reclass of conversion premium - convertible notes												$ (700,000)
Gregory Funding LLC
Debt Instrument [Line Items]
Ceiling for each repurchase facility			12,000,000					$ 12,000,000			$ 2,000,000		$ 3,500,000
Convertible notes payable
Debt Instrument [Line Items]
Interest expense			$ 1,900,000		2,100,000			$ 4,000,000	4,200,000
Master repurchase agreement
Debt Instrument [Line Items]
Interest rate (in percent)			7.12%					7.12%		6.31%
Amount outstanding			$ 413,125,000					$ 413,125,000		$ 445,855,000
Servicing agreement | Minimum | Gregory Funding LLC
Debt Instrument [Line Items]
Servicing fees (in percent)								0.65%
Servicing agreement | Maximum | Gregory Funding LLC
Debt Instrument [Line Items]
Servicing fees (in percent)								1.25%
Mortgage loans | Ajax Mortgage Loan Trust 2017-D/ December 2017
Debt Instrument [Line Items]
Ownership percentage by parent (in percent)														50.00%
Mortgage loans | Non-rated secured borrowings
Debt Instrument [Line Items]
Number of securitizations outstanding | securitization			1					1
Mortgage loans | Rated secured borrowings
Debt Instrument [Line Items]
Number of securitizations outstanding | securitization			4					4
Convertible notes payable
Debt Instrument [Line Items]
Interest rate (in percent)			7.25%					7.25%
Principal amount of note (in dollars per share) | $ / shares								$ 25.00
If-converted value in excess of principal								$ 59,300,000
Unpaid principal balance			$ 103,500,000					103,500,000		104,500,000
Interest expense			2,700,000					5,300,000
Amortization of debt discount			$ 100,000		$ 200,000			$ 300,000	$ 400,000
Interest rate, effective percentage			7.51%		8.04%			7.51%	8.04%
Debt instrument, repurchase amount			$ 0	$ 1,000,000	$ 100,000			$ 0	$ 100,000
Repurchase of the company's senior convertible notes				$ 1,000,000	$ 100,000
Repayments of convertible debt						$ 0
Threshold percentage of stock price trigger (at least) (in percent)								130.00%
Threshold trading days (at least) | day								20
Threshold consecutive trading days | day								30
Redemption price, percentage								100.00%
Amortization of debt discount and deferred expenses			$ 200,000					$ 400,000
Convertible notes payable | Common stock
Debt Instrument [Line Items]
Conversion rate								1.7405
Conversion price (in dollars per share) | $ / shares			$ 14.36					$ 14.36
Convertible Debt
Debt Instrument [Line Items]
Debt issuance costs, net			$ 0					$ 0		(300,000)
Senior notes | 8.875% Senior Unsecured Notes Due September 2027
Debt Instrument [Line Items]
Interest rate (in percent)		8.875%
Interest rate, effective percentage			9.98%					9.98%
Aggregate principal		$ 110,000,000
Debt instrument, term (in years)		5 years
Issuance amount, amount of par value (percent)		0.99009
Proceeds from unsecured notes payable		$ 106,100,000
Proceeds used to repurchase and retire securities			$ 90,000,000					$ 90,000,000
Amount outstanding			110,000,000					110,000,000		110,000,000
Notes Payable
Debt Instrument [Line Items]
Debt issuance costs, net			(3,600,000)					$ (3,600,000)		$ (4,000,000)
Delaware Trust | Mortgage loans | Master repurchase agreement
Debt Instrument [Line Items]
Number of facilities repurchased | facility								2
Number of wholly-owned Delaware trusts | trust								2
Number of counterparties | counterparty								2
Ceiling for each repurchase facility			150,000,000					$ 150,000,000
Delaware Trust | Mortgage loans | Master repurchase agreement | Minimum
Debt Instrument [Line Items]
Percentage of purchase price for each mortgage loan or REO (in percentage)								75.00%
Delaware Trust | Mortgage loans | Master repurchase agreement | Maximum
Debt Instrument [Line Items]
Percentage of purchase price for each mortgage loan or REO (in percentage)								90.00%
Delaware Trust | Mortgages one | Master repurchase agreement
Debt Instrument [Line Items]
Ceiling for each repurchase facility			$ 400,000,000					$ 400,000,000
Delaware Trust | Bonds | Master repurchase agreement
Debt Instrument [Line Items]
Number of facilities repurchased | facility								4

[1] Secured borrowings, net are presented net of deferred issuance costs of $3.8 million at June 30, 2023 and $4.7 million at December 31, 2022. Convertible senior notes, net are presented net of deferred issuance costs of zero and $0.3 million at June 30, 2023 and December 31, 2022, respectively. Notes payable, net are presented net of deferred issuance costs and discount of $3.6 million at June 30, 2023 and $4.0 million at December 31, 2022.