Fair Value Measurements - Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments (Details) $ in Thousands	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated Fair Value	$ 2,283,262	$ 2,411,622
Trading investments	60,473	$ 54,481
Level 3  | Valuation Technique, Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated Fair Value	3,107
Trading investments	60,473
Total	$ 63,580
Level 3  | Valuation Technique, Discounted Cash Flow | Minimum | Measurement Input, Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities	0.071
Residual Interests	0.071
Level 3  | Valuation Technique, Discounted Cash Flow | Minimum | Measurement Input, Default Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities	0.040
Residual Interests	0.040
Level 3  | Valuation Technique, Discounted Cash Flow | Maximum | Measurement Input, Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities	0.111
Residual Interests	0.111
Level 3  | Valuation Technique, Discounted Cash Flow | Maximum | Measurement Input, Default Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities	0.174
Residual Interests	0.174
Level 3  | Valuation Technique, Discounted Cash Flow | Weighted Average | Measurement Input, Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities	0.0849
Residual Interests	0.0849
Level 3  | Valuation Technique, Discounted Cash Flow | Weighted Average | Measurement Input, Default Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities	0.1126
Residual Interests	0.1126