Fair Value Measurement - Sensitivity of Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Aggregate fair value of loans purchased and held	$ 252,477	$ 78,460
Loans (at fair value)
Discount rates
100 basis point increase	(3,392)	(979)
200 basis point increase	(6,709)	(1,939)
Expected credit loss rates on underlying loans
10% adverse change	(3,959)	(1,303)
20% adverse change	(7,927)	(2,611)
Fair Value, Inputs, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Aggregate fair value of loans purchased and held	252,477	78,460
Fair Value, Inputs, Level 3 | Loans (at fair value)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Aggregate fair value of loans purchased and held	$ 252,477	$ 78,460