Regulatory Capital and Liquidity Requirements - Summary of Capital and Liquidity Amounts and Requirements by Agencies (Detail) $ in Thousands |
Sep. 30, 2026
USD ($)
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Dec. 31, 2025
USD ($)
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|---|---|---|---|---|
| Capital Requirements By Agencies [Line Items] | ||||
| Net worth, Actual | [1] | $ 689,846 | $ 682,481 | |
| Net worth, Required | [1] | $ 526,908 | $ 569,435 | |
| Tangible net worth / total assets ratio, Actual | [1] | 0.09 | 0.09 | |
| Tangible net worth / total assets ratio, Required | [1] | 0.06 | 0.06 | |
| Liquidity, Actual | [1] | $ 337,337 | $ 514,626 | |
| Liquidity, Required | [1] | $ 191,858 | $ 211,818 | |
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