Fair Value of Financial Assets and Liabilities - Schedule of Fair Value Hierarchy for Financial Assets and Liabilities Not Recorded at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Jun. 30, 2025
Level 1
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Loans held for sale	$ 0
Loans held for investment, net	0	$ 0
Total assets	0	0
Convertible senior notes, net	0	0
Notes issued by securitization trusts	0	0
Funding debt	0	0
Total liabilities	0	0
Level 2
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Loans held for sale	1
Loans held for investment, net	0	0
Total assets	1	0
Convertible senior notes, net	1,286,525	1,205,287
Notes issued by securitization trusts	0	0
Funding debt	0	0
Total liabilities	1,286,525	1,205,287
Level 3
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Loans held for sale	0
Loans held for investment, net	9,814,199	7,085,840
Total assets	9,814,199	7,085,840
Convertible senior notes, net	0	0
Notes issued by securitization trusts	5,341,418	4,868,980
Funding debt	3,359,290	1,640,765
Total liabilities	8,700,708	6,509,745
Carrying Amount
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Loans held for sale	1
Loans held for investment, net	8,997,447	6,628,606
Total assets	8,997,448	6,628,606
Convertible senior notes, net	1,129,581	1,153,000
Notes issued by securitization trusts	5,331,229	4,833,855
Funding debt	3,333,248	1,622,808
Total liabilities	9,794,058	7,609,663
Carrying Amount \| 2026 Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Convertible senior notes, net	221,100	247,900
Carrying Amount \| 2029 Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Convertible senior notes, net	908,500	905,100
Balance at Fair Value
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Loans held for sale	1
Loans held for investment, net	9,814,199	7,085,840
Total assets	9,814,200	7,085,840
Convertible senior notes, net	1,286,525	1,205,287
Notes issued by securitization trusts	5,341,418	4,868,980
Funding debt	3,359,290	1,640,765
Total liabilities	9,987,233	7,715,032
Balance at Fair Value \| 2026 Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Convertible senior notes, net	217,800	232,700
Balance at Fair Value \| 2029 Notes
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Convertible senior notes, net	$ 1,100,000	$ 972,600