Fair Value Measurements - Assets and Liabilities, Not at FV (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets:
Investments held to maturity	$ 3,446	$ 3,446
Purchased future receivables, net	2,093	9,483
Investment in unconsolidated joint venture	6,974	7,360
Liabilities:
Senior secured notes, net	417,040	345,127
Carrying Amount
Assets:
Loans, held-for-investment	9,446,288	10,622,137
Loans, held for sale	452,856
Servicing rights	119,768	102,837
Total assets	10,018,912	10,724,974
Liabilities:
Secured borrowings	2,311,969	2,102,075
Securitized debt obligations of consolidated VIEs	4,407,241	5,068,453
Senior secured notes, net	417,040	345,127
Guaranteed loan financing	782,345	844,540
Corporate debt, net	767,271	764,908
Total liabilities	8,685,866	9,125,103
Fair Value
Assets:
Loans, held-for-investment	9,255,383	10,380,893
Loans, held for sale	452,856
Servicing rights	129,471	113,715
Total assets	9,837,710	10,494,608
Liabilities:
Secured borrowings	2,311,969	2,102,075
Securitized debt obligations of consolidated VIEs	4,361,392	5,022,057
Senior secured notes, net	395,879	317,239
Guaranteed loan financing	828,902	889,744
Corporate debt, net	717,056	731,104
Total liabilities	$ 8,615,198	$ 9,062,219