Basis of Presentation - Schedule of Intangible Assets – Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-lived Intangible Assets [Roll Forward]
Accumulated Amortization at December 31, 2020	$ (16,000)	$ (9,000)
Carrying Value at December 31, 2020	56,865
5 Arches LLC And CoreVest
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets at Acquisition	81,300	81,300
Accumulated Amortization at December 31, 2020	(24,435)	(8,511)
Carrying Value at December 31, 2020	$ 56,865	$ 72,789
Weighted Average Amortization Period (in years)	6 years	6 years
Borrower network | 5 Arches LLC And CoreVest
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets at Acquisition	$ 45,300	$ 45,300
Accumulated Amortization at December 31, 2020	(7,819)	(1,348)
Carrying Value at December 31, 2020	$ 37,481	$ 43,952
Weighted Average Amortization Period (in years)	7 years	7 years
Broker network | 5 Arches LLC And CoreVest
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets at Acquisition	$ 18,100	$ 18,100
Accumulated Amortization at December 31, 2020	(6,637)	(3,017)
Carrying Value at December 31, 2020	$ 11,463	$ 15,083
Weighted Average Amortization Period (in years)	5 years	5 years
Non-compete agreements | 5 Arches LLC And CoreVest
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets at Acquisition	$ 9,500	$ 9,500
Accumulated Amortization at December 31, 2020	(4,431)	(1,264)
Carrying Value at December 31, 2020	$ 5,069	$ 8,236
Weighted Average Amortization Period (in years)	3 years	3 years
Tradenames | 5 Arches LLC And CoreVest
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets at Acquisition	$ 4,000	$ 4,000
Accumulated Amortization at December 31, 2020	(1,860)	(527)
Carrying Value at December 31, 2020	$ 2,140	$ 3,473
Weighted Average Amortization Period (in years)	3 years	3 years
Developed technology | 5 Arches LLC And CoreVest
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets at Acquisition	$ 1,800	$ 1,800
Accumulated Amortization at December 31, 2020	(1,088)	(188)
Carrying Value at December 31, 2020	$ 712	$ 1,612
Weighted Average Amortization Period (in years)	2 years	2 years
Loan administration fees on existing loan assets | 5 Arches LLC And CoreVest
Finite-lived Intangible Assets [Roll Forward]
Intangible Assets at Acquisition	$ 2,600	$ 2,600
Accumulated Amortization at December 31, 2020	(2,600)	(2,167)
Carrying Value at December 31, 2020	$ 0	$ 433
Weighted Average Amortization Period (in years)	1 year	1 year