Fair Value - Financial Instruments Not Carried at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial assets not carried at fair value:
HTM debt securities	$ 691,746	$ 544,280
Carrying Value
Financial assets not carried at fair value:
Loans held-for-investment and loans held-for-sale	15,477,624	11,116,929
HTM debt securities	683,136	538,605
Financial liabilities not carried at fair value:
Secured financing agreements, CLOs and SASB	15,192,966	11,076,744
Unsecured senior notes	1,828,590	1,732,520
Fair Value
Financial assets not carried at fair value:
Loans held-for-investment and loans held-for-sale	15,526,235	11,107,316
HTM debt securities	656,864	515,253
Financial liabilities not carried at fair value:
Secured financing agreements, CLOs and SASB	15,266,440	11,108,364
Unsecured senior notes	$ 1,893,065	$ 1,786,667