Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Assets
Loans held for sale at fair value	$ 1,008,168	$ 636,352
Loans held for investment at fair value	631,736	1,027,798
Securities available for sale:
Total securities available for sale	3,527,142	3,452,648
Servicing assets	57,909	60,697
Other assets	1,968	5,820
Total assets	5,226,923	5,183,315
Liabilities:
Other liabilities	9,364	16,818
Total liabilities	9,364	16,818
Senior asset-backed securities related to Structured Program transactions
Securities available for sale:
Total securities available for sale	2,962,475	2,899,824
U.S. agency residential mortgage-backed securities
Securities available for sale:
Total securities available for sale	227,617	226,925
Other asset-backed securities related to Structured Program transactions
Securities available for sale:
Total securities available for sale	184,032	169,948
U.S. agency securities
Securities available for sale:
Total securities available for sale	75,134	75,946
Mortgage-backed securities
Securities available for sale:
Total securities available for sale	56,553	56,674
Other asset-backed securities
Securities available for sale:
Total securities available for sale	18,871	20,792
Municipal securities
Securities available for sale:
Total securities available for sale	2,460	2,539
Level 1
Assets
Loans held for sale at fair value	0	0
Loans held for investment at fair value	0	0
Securities available for sale:
Total securities available for sale	0	0
Servicing assets	0	0
Other assets	0	0
Total assets	0	0
Liabilities:
Other liabilities	0	0
Total liabilities	0	0
Level 1 \| Senior asset-backed securities related to Structured Program transactions
Securities available for sale:
Total securities available for sale	0	0
Level 1 \| U.S. agency residential mortgage-backed securities
Securities available for sale:
Total securities available for sale	0	0
Level 1 \| Other asset-backed securities related to Structured Program transactions
Securities available for sale:
Total securities available for sale	0	0
Level 1 \| U.S. agency securities
Securities available for sale:
Total securities available for sale	0	0
Level 1 \| Mortgage-backed securities
Securities available for sale:
Total securities available for sale	0	0
Level 1 \| Other asset-backed securities
Securities available for sale:
Total securities available for sale	0	0
Level 1 \| Municipal securities
Securities available for sale:
Total securities available for sale	0	0
Level 2
Assets
Loans held for sale at fair value	0	0
Loans held for investment at fair value	0	0
Securities available for sale:
Total securities available for sale	380,635	382,876
Servicing assets	0	0
Other assets	1,968	5,820
Total assets	382,603	388,696
Liabilities:
Other liabilities	3,513	5,019
Total liabilities	3,513	5,019
Level 2 \| Senior asset-backed securities related to Structured Program transactions
Securities available for sale:
Total securities available for sale	0	0
Level 2 \| U.S. agency residential mortgage-backed securities
Securities available for sale:
Total securities available for sale	227,617	226,925
Level 2 \| Other asset-backed securities related to Structured Program transactions
Securities available for sale:
Total securities available for sale	0	0
Level 2 \| U.S. agency securities
Securities available for sale:
Total securities available for sale	75,134	75,946
Level 2 \| Mortgage-backed securities
Securities available for sale:
Total securities available for sale	56,553	56,674
Level 2 \| Other asset-backed securities
Securities available for sale:
Total securities available for sale	18,871	20,792
Level 2 \| Municipal securities
Securities available for sale:
Total securities available for sale	2,460	2,539
Level 3
Assets
Loans held for sale at fair value	1,008,168	636,352
Loans held for investment at fair value	631,736	1,027,798
Securities available for sale:
Total securities available for sale	3,146,507	3,069,772
Servicing assets	57,909	60,697
Other assets	0	0
Total assets	4,844,320	4,794,619
Liabilities:
Other liabilities	5,851	11,799
Total liabilities	5,851	11,799
Level 3 \| Senior asset-backed securities related to Structured Program transactions
Securities available for sale:
Total securities available for sale	2,962,475	2,899,824
Level 3 \| U.S. agency residential mortgage-backed securities
Securities available for sale:
Total securities available for sale	0	0
Level 3 \| Other asset-backed securities related to Structured Program transactions
Securities available for sale:
Total securities available for sale	184,032	169,948
Level 3 \| U.S. agency securities
Securities available for sale:
Total securities available for sale	0	0
Level 3 \| Mortgage-backed securities
Securities available for sale:
Total securities available for sale	0	0
Level 3 \| Other asset-backed securities
Securities available for sale:
Total securities available for sale	0	0
Level 3 \| Municipal securities
Securities available for sale:
Total securities available for sale	$ 0	$ 0

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Fair value portion of asset recognized for present right to economic benefit.

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Fair value of financial and nonfinancial obligations.

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